---
layout: docs
page_title: Telemetry
description: >-
  The Consul agent collects various runtime metrics about the performance of
  different libraries and subsystems. These metrics are aggregated on a ten
  second interval and are retained for one minute.
---

# Telemetry

The Consul agent collects various runtime metrics about the performance of
different libraries and subsystems. These metrics are aggregated on a ten
second (10s) interval and are retained for one minute. An _interval_ is the period of time between instances of data being collected and aggregated.

When telemetry is being streamed to an external metrics store, the interval is defined to be that store's flush interval.

|External Store|Interval (seconds)|
|:--------|:--------|
|[dogstatsd](https://docs.datadoghq.com/developers/dogstatsd/?tab=hostagent#how-it-works)|10s|
|[Prometheus](https://vector.dev/docs/reference/configuration/sinks/prometheus_exporter/#flush_period_secshttps://vector.dev/docs/reference/configuration/sinks/prometheus_exporter/#flush_period_secs)| 60s|
|[statsd](https://github.com/statsd/statsd/blob/master/docs/metric_types.md#timing)|10s|

To view this data, you must send a signal to the Consul process: on Unix,
this is `USR1` while on Windows it is `BREAK`. Once Consul receives the signal,
it will dump the current telemetry information to the agent's `stderr`.

This telemetry information can be used for debugging or otherwise
getting a better view of what Consul is doing. Review the [Monitoring and
Metrics tutorial](https://learn.hashicorp.com/tutorials/consul/monitor-datacenter-health?utm_source=consul.io&utm_medium=docs) to learn how collect and interpret Consul data.

Additionally, if the [`telemetry` configuration options](/docs/agent/options#telemetry)
are provided, the telemetry information will be streamed to a
[statsite](http://github.com/armon/statsite) or [statsd](http://github.com/etsy/statsd) server where
it can be aggregated and flushed to Graphite or any other metrics store.
For a configuration example for Telegraf, review the [Monitoring with Telegraf tutorial](https://learn.hashicorp.com/tutorials/consul/monitor-health-telegraf?utm_source=consul.io&utm_medium=docs).

This
information can also be viewed with the [metrics endpoint](/api/agent#view-metrics) in JSON
format or using [Prometheus](https://prometheus.io/) format.

Below is sample output of a telemetry dump:

```log
[2014-01-29 10:56:50 -0800 PST][G] 'consul-agent.runtime.num_goroutines': 19.000
[2014-01-29 10:56:50 -0800 PST][G] 'consul-agent.runtime.alloc_bytes': 755960.000
[2014-01-29 10:56:50 -0800 PST][G] 'consul-agent.runtime.malloc_count': 7550.000
[2014-01-29 10:56:50 -0800 PST][G] 'consul-agent.runtime.free_count': 4387.000
[2014-01-29 10:56:50 -0800 PST][G] 'consul-agent.runtime.heap_objects': 3163.000
[2014-01-29 10:56:50 -0800 PST][G] 'consul-agent.runtime.total_gc_pause_ns': 1151002.000
[2014-01-29 10:56:50 -0800 PST][G] 'consul-agent.runtime.total_gc_runs': 4.000
[2014-01-29 10:56:50 -0800 PST][C] 'consul-agent.agent.ipc.accept': Count: 5 Sum: 5.000
[2014-01-29 10:56:50 -0800 PST][C] 'consul-agent.agent.ipc.command': Count: 10 Sum: 10.000
[2014-01-29 10:56:50 -0800 PST][C] 'consul-agent.serf.events': Count: 5 Sum: 5.000
[2014-01-29 10:56:50 -0800 PST][C] 'consul-agent.serf.events.foo': Count: 4 Sum: 4.000
[2014-01-29 10:56:50 -0800 PST][C] 'consul-agent.serf.events.baz': Count: 1 Sum: 1.000
[2014-01-29 10:56:50 -0800 PST][S] 'consul-agent.memberlist.gossip': Count: 50 Min: 0.007 Mean: 0.020 Max: 0.041 Stddev: 0.007 Sum: 0.989
[2014-01-29 10:56:50 -0800 PST][S] 'consul-agent.serf.queue.Intent': Count: 10 Sum: 0.000
[2014-01-29 10:56:50 -0800 PST][S] 'consul-agent.serf.queue.Event': Count: 10 Min: 0.000 Mean: 2.500 Max: 5.000 Stddev: 2.121 Sum: 25.000
```

# Key Metrics

These are some metrics emitted that can help you understand the health of your cluster at a glance. A [Grafana dashboard](https://grafana.com/grafana/dashboards/13396) is also available, which is maintained by the Consul team and displays these metrics for easy visualization. For a full list of metrics emitted by Consul, see [Metrics Reference](#metrics-reference)

### Transaction timing

| Metric Name              | Description                                                                          | Unit                         | Type    |
| :----------------------- | :----------------------------------------------------------------------------------- | :--------------------------- | :------ |
| `consul.kvs.apply`       | Measures the time it takes to complete an update to the KV store.               | ms                           | timer   |
| `consul.txn.apply`       | Measures the time spent applying a transaction operation.                       | ms                           | timer   |
| `consul.raft.apply`      | Counts the number of Raft transactions applied during the interval. This metric is only reported on the leader. | raft transactions / interval | counter |
| `consul.raft.commitTime` | Measures the time it takes to commit a new entry to the Raft log on the leader. | ms                           | timer   |

**Why they're important:** Taken together, these metrics indicate how long it takes to complete write operations in various parts of the Consul cluster. Generally these should all be fairly consistent and no more than a few milliseconds. Sudden changes in any of the timing values could be due to unexpected load on the Consul servers, or due to problems on the servers themselves.

**What to look for:** Deviations (in any of these metrics) of more than 50% from baseline over the previous hour.

### Leadership changes

| Metric Name                      | Description                                                                                                    | Unit      | Type    |
| :------------------------------- | :------------------------------------------------------------------------------------------------------------- | :-------- | :------ |
| `consul.raft.leader.lastContact` | Measures the time since the leader was last able to contact the follower nodes when checking its leader lease. | ms        | timer   |
| `consul.raft.state.candidate`    | Increments whenever a Consul server starts an election.                                                   | elections | counter |
| `consul.raft.state.leader`       | Increments whenever a Consul server becomes a leader.                                                     | leaders   | counter |

**Why they're important:** Normally, your Consul cluster should have a stable leader. If there are frequent elections or leadership changes, it would likely indicate network issues between the Consul servers, or that the Consul servers themselves are unable to keep up with the load.

**What to look for:** For a healthy cluster, you're looking for a `lastContact` lower than 200ms, `leader` > 0 and `candidate` == 0. Deviations from this might indicate flapping leadership.

### Autopilot

| Metric Name                | Description                                                                                                                                                                  | Unit         | Type  |
| :------------------------- | :--------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :----------- | :---- |
| `consul.autopilot.healthy` | Tracks the overall health of the local server cluster. If all servers are considered healthy by Autopilot, this will be set to 1. If any are unhealthy, this will be 0. All non-leader servers will report `NaN`. | health state | gauge |

**Why it's important:** Autopilot can expose the overall health of your cluster with a simple boolean.

**What to look for:** Alert if `healthy` is 0. Some other indicators of an unhealthy cluster would be:
- `consul.raft.commitTime` - This can help reflect the speed of state store
changes being performed by the agent. If this number is rising, the server may
be experiencing an issue due to degraded resources on the host.
- [Leadership change metrics](#leadership-changes) - Check for deviation from
the recommended values. This can indicate failed leadership elections or
flapping nodes.

### Memory usage

| Metric Name                  | Description                                                        | Unit  | Type  |
| :--------------------------- | :----------------------------------------------------------------- | :---- | :---- |
| `consul.runtime.alloc_bytes` | Measures the number of bytes allocated by the Consul process. | bytes | gauge |
| `consul.runtime.sys_bytes`   | Measures the total number of bytes of memory obtained from the OS.  | bytes | gauge |

**Why they're important:** Consul keeps all of its data in memory. If Consul consumes all available memory, it will crash.

**What to look for:** If `consul.runtime.sys_bytes` exceeds 90% of total available system memory.

**NOTE:** This metric is calculated using Go's runtime package
[MemStats](https://golang.org/pkg/runtime/#MemStats). This will have a
different output than using information gathered from `top`. For more
information, see [GH-4734](https://github.com/hashicorp/consul/issues/4734).

### Garbage collection

| Metric Name                        | Description                                                                                           | Unit | Type  |
| :--------------------------------- | :---------------------------------------------------------------------------------------------------- | :--- | :---- |
| `consul.runtime.total_gc_pause_ns` | Number of nanoseconds consumed by stop-the-world garbage collection (GC) pauses since Consul started. | ns   | gauge |

**Why it's important:** GC pause is a "stop-the-world" event, meaning that all runtime threads are blocked until GC completes. Normally these pauses last only a few nanoseconds. But if memory usage is high, the Go runtime may GC so frequently that it starts to slow down Consul.

**What to look for:** Warning if `total_gc_pause_ns` exceeds 2 seconds/minute, critical if it exceeds 5 seconds/minute.

**NOTE:** `total_gc_pause_ns` is a cumulative counter, so in order to calculate rates (such as GC/minute),
you will need to apply a function such as InfluxDB's [`non_negative_difference()`](https://docs.influxdata.com/influxdb/v1.5/query_language/functions/#non-negative-difference).

### Network activity - RPC Count

| Metric Name                  | Description                                                                                                                                                                       | Unit     | Type    |
| :--------------------------- | :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :------- | :------ |
| `consul.client.rpc`          | Increments whenever a Consul agent in client mode makes an RPC request to a Consul server                                                                                         | requests | counter |
| `consul.client.rpc.exceeded` | Increments whenever a Consul agent in client mode makes an RPC request to a Consul server gets rate limited by that agent's [`limits`](/docs/agent/options#limits) configuration. | requests | counter |
| `consul.client.rpc.failed`   | Increments whenever a Consul agent in client mode makes an RPC request to a Consul server and fails.                                                                              | requests | counter |

**Why they're important:** These measurements indicate the current load created from a Consul agent, including when the load becomes high enough to be rate limited. A high RPC count, especially from `consul.client.rpcexceeded` meaning that the requests are being rate-limited, could imply a misconfigured Consul agent.

**What to look for:**
Sudden large changes to the `consul.client.rpc` metrics (greater than 50% deviation from baseline).
`consul.client.rpc.exceeded` or `consul.client.rpc.failed` count > 0, as it implies that an agent is being rate-limited or fails to make an RPC request to a Consul server

### Raft Replication Capacity Issues

| Metric Name                  | Description                                                                                                                                                                       | Unit     | Type    |
| :--------------------------- | :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :------- | :------ |
| `consul.raft.fsm.lastRestoreDuration`               | Measures the time taken to restore the FSM from a snapshot on an agent restart or from the leader calling installSnapshot. This is a gauge that holds it's value since most servers only restore during restarts which are typically infrequent.                                                                                                                                                                                                                                                                                                                                                                                                              | ms                                | gauge   |
| `consul.raft.leader.oldestLogAge`                   | The number of milliseconds since the _oldest_ log in the leader's log store was written. This can be important for replication health where write rate is high and the snapshot is large as followers may be unable to recover from a restart if restoring takes longer than the minimum value for the current leader. Compare this with `consul.raft.fsm.lastRestoreDuration` and `consul.raft.rpc.installSnapshot` to monitor. In normal usage this gauge value will grow linearly over time until a snapshot completes on the leader and the log is truncated.                                                                                             | ms                                | gauge   |
| `consul.raft.rpc.installSnapshot`                   | Measures the time taken to process the installSnapshot RPC call. This metric should only be seen on agents which are currently in the follower state.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         | ms                                | timer   |

**Why they're important:** These metrics allow operators to monitor the health
and capacity of raft replication on servers. **When Consul is handling large
amounts of data and high write throughput** it is possible for the cluster to
get into the following state:
 * Write throughput is high (say 500 commits per second or more) and constant
 * The leader is writing out a large snapshot every minute or so
 * The snapshot is large enough that it takes considerable time to restore from
   disk on a restart or from the leader if a follower gets behind
 * Disk IO available allows the leader to write a snapshot faster than it can be
   restored from disk on a follower

Under these conditions, a follower after a restart may be unable to catch up on
replication and become a voter again since it takes longer to restore from disk
or the leader than the leader takes to write a new snapshot and truncate its
logs. Servers retain
[`raft_trailing_logs`](/docs/agent/options#_raft_trailing_logs) (default
`10240`) log entries even if their snapshot was more recent. On a leader
processing 500 commits/second, that is only about 20 seconds worth of logs.
Assuming the leader is able to write out a snapshot and truncate the logs in
less than 20 seconds, there will only be 20 seconds worth of "recent" logs
available on the leader right after the leader has taken a snapshot and never
more than about 80 seconds worth assuming it is taking a snapshot and truncating
logs every 60 seconds.

In this state, followers must be able to restore a snapshot into memory and
resume replication in under 80 seconds otherwise they will never be able to
rejoin the cluster until write rates reduce. If they take more than 20 seconds
then there will be a chance that they are unlucky with timing when they restart
and have to download a snapshot again from the servers one or more times. If
they take 50 seconds or more then they will likely fail to catch up more often
than they succeed and will remain non-voters for some time until they happen to
complete the restore just before the leader truncates its logs.

In the worst case, the follower will be left continually downloading snapshots
from the leader which are always too old to use by the time they are restored.
This can put additional strain on the leader transferring large snapshots
repeatedly as well as reduce the fault tolerance and serving capacity of the
cluster.

Since Consul 1.5.3
[`raft_trailing_logs`](/docs/agent/options#_raft_trailing_logs) has been
configurable. Increasing it allows the leader to retain more logs and give
followers more time to restore and catch up. The tradeoff is potentially
slower appends which eventually might affect write throughput and latency
negatively so setting it arbitrarily high is not recommended. Before Consul
1.10.0 it required a rolling restart to change this configuration on the leader
though and since no followers could restart without loosing health this could
mean loosing cluster availability and needing to recover the cluster from a loss
of quorum.

Since Consul 1.10.0
[`raft_trailing_logs`](/docs/agent/options#_raft_trailing_logs) is now
reloadable with `consul reload` or `SIGHUP` allowing operators to increase this
without the leader restarting or loosing leadership allowing the cluster to be
recovered gracefully.

Monitoring these metrics can help avoid or diagnose this state.

**What to look for:**

`consul.raft.leader.oldestLogAge` should look like a saw-tooth wave increasing
linearly with time until the leader takes a snapshot and then jumping down as
the oldest logs are truncated. The lowest point on that line should remain
comfortably higher (i.e. 2x or more) than the time it takes to restore a
snapshot.

There are two ways a snapshot can be restored on a follower: from disk on
startup or from the leader during an `installSnapshot` RPC. The leader only
sends an `installSnapshot` RPC if the follower is new and has no state, or if
it's state is too old for it to catch up with the leaders logs.

`consul.raft.fsm.lastRestoreDuration` shows the time it took to restore from
either source the last time it happened. Most of the time this is when the
server was started. It's a gauge that will always show the last restore duration
(in Consul 1.10.0 and later) however long ago that was.

`consul.raft.rpc.installSnapshot` is the timing information from the leader's
perspective when it installs a new snapshot on a follower. It includes the time
spent transferring the data as well as the follower restoring it. Since these
events are typically infrequent, you may need to graph the last value observed,
for example using `max_over_time` with a large range in Prometheus. While the
restore part will also be reflected in `lastRestoreDuration`, it can be useful
to observe this too since the logs need to be able to cover this entire
operation including the snapshot delivery to ensure followers can always catch
up safely.

Graphing `consul.raft.leader.oldestLogAge` on the same axes as the other two
metrics here can help see at a glance if restore times are creeping dangerously
close to the limit of what the leader is retaining at the current write rate.

Note that if servers don't restart often, then the snapshot could have grown
significantly since the last restore happened so last restore times might not
reflect what would happen if an agent restarts now.

### License Expiration <EnterpriseAlert inline />

| Metric Name                       | Description                                                      | Unit  | Type  |
| :-------------------------------- | :--------------------------------------------------------------- | :---- | :---- |
| `consul.system.licenseExpiration` | Number of hours until the Consul Enterprise license will expire. | hours | gauge |

**Why they're important:**

This measurement indicates how many hours are left before the Consul Enterprise license expires. When the license expires some
Consul Enterprise features will cease to work. An example of this is that after expiration, it is no longer possible to create
or modify resources in non-default namespaces or to manage namespace definitions themselves even though reads of namespaced
resources will still work.

**What to look for:**

This metric should be monitored to ensure that the license doesn't expire to prevent degradation of functionality.


## Metrics Reference

This is a full list of metrics emitted by Consul.

| Metric                                                   | Description                                                                                                                                                                                                                                                                                                                                                                                                         | Unit                 | Type    |
| -------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------- | ------- |
| `consul.acl.blocked.{check,service}.deregistration` | Increments whenever a deregistration fails for an entity (check or service) is blocked by an ACL.                                                                                                                                                                                                                                                                                                                        | requests             | counter |
| `consul.acl.blocked.{check,node,service}.registration`   | Increments whenever a registration fails for an entity (check, node or service) is blocked by an ACL.                                                                                                                                                                                                                                                                                                               | requests             | counter |
| `consul.api.http`                                        | Migrated from consul.http.. this samples how long it takes to service the given HTTP request for the given verb and path. Includes labels for `path` and `method`. `path` does not include details like service or key names, for these an underscore will be present as a placeholder (eg. path=`v1.kv._`)                                                                                                         | ms                   | timer   |
| `consul.client.rpc`                                      | Increments whenever a Consul agent in client mode makes an RPC request to a Consul server. This gives a measure of how much a given agent is loading the Consul servers. Currently, this is only generated by agents in client mode, not Consul servers.                                                                                                                                                            | requests             | counter |
| `consul.client.rpc.exceeded`                             | Increments whenever a Consul agent in client mode makes an RPC request to a Consul server gets rate limited by that agent's [`limits`](/docs/agent/options#limits) configuration. This gives an indication that there's an abusive application making too many requests on the agent, or that the rate limit needs to be increased. Currently, this only applies to agents in client mode, not Consul servers.      | rejected requests    | counter |
| `consul.client.rpc.failed`                               | Increments whenever a Consul agent in client mode makes an RPC request to a Consul server and fails.                                                                                                                                                                                                                                                                                                                | requests             | counter |
| `consul.client.api.catalog_register.`                    | Increments whenever a Consul agent receives a catalog register request.                                                                                                                                                                                                                                                                                                                                             | requests             | counter |
| `consul.client.api.success.catalog_register.`            | Increments whenever a Consul agent successfully responds to a catalog register request.                                                                                                                                                                                                                                                                                                                             | requests             | counter |
| `consul.client.rpc.error.catalog_register.`              | Increments whenever a Consul agent receives an RPC error for a catalog register request.                                                                                                                                                                                                                                                                                                                            | errors               | counter |
| `consul.client.api.catalog_deregister.`                  | Increments whenever a Consul agent receives a catalog deregister request.                                                                                                                                                                                                                                                                                                                                           | requests             | counter |
| `consul.client.api.success.catalog_deregister.`          | Increments whenever a Consul agent successfully responds to a catalog deregister request.                                                                                                                                                                                                                                                                                                                           | requests             | counter |
| `consul.client.rpc.error.catalog_deregister.`            | Increments whenever a Consul agent receives an RPC error for a catalog deregister request.                                                                                                                                                                                                                                                                                                                          | errors               | counter |
| `consul.client.api.catalog_datacenters.`                 | Increments whenever a Consul agent receives a request to list datacenters in the catalog.                                                                                                                                                                                                                                                                                                                           | requests             | counter |
| `consul.client.api.success.catalog_datacenters.`         | Increments whenever a Consul agent successfully responds to a request to list datacenters.                                                                                                                                                                                                                                                                                                                          | requests             | counter |
| `consul.client.rpc.error.catalog_datacenters.`           | Increments whenever a Consul agent receives an RPC error for a request to list datacenters.                                                                                                                                                                                                                                                                                                                         | errors               | counter |
| `consul.client.api.catalog_nodes.`                       | Increments whenever a Consul agent receives a request to list nodes from the catalog.                                                                                                                                                                                                                                                                                                                               | requests             | counter |
| `consul.client.api.success.catalog_nodes.`               | Increments whenever a Consul agent successfully responds to a request to list nodes.                                                                                                                                                                                                                                                                                                                                | requests             | counter |
| `consul.client.rpc.error.catalog_nodes.`                 | Increments whenever a Consul agent receives an RPC error for a request to list nodes.                                                                                                                                                                                                                                                                                                                               | errors               | counter |
| `consul.client.api.catalog_services.`                    | Increments whenever a Consul agent receives a request to list services from the catalog.                                                                                                                                                                                                                                                                                                                            | requests             | counter |
| `consul.client.api.success.catalog_services.`            | Increments whenever a Consul agent successfully responds to a request to list services.                                                                                                                                                                                                                                                                                                                             | requests             | counter |
| `consul.client.rpc.error.catalog_services.`              | Increments whenever a Consul agent receives an RPC error for a request to list services.                                                                                                                                                                                                                                                                                                                            | errors               | counter |
| `consul.client.api.catalog_service_nodes.`               | Increments whenever a Consul agent receives a request to list nodes offering a service.                                                                                                                                                                                                                                                                                                                             | requests             | counter |
| `consul.client.api.success.catalog_service_nodes.`       | Increments whenever a Consul agent successfully responds to a request to list nodes offering a service.                                                                                                                                                                                                                                                                                                             | requests             | counter |
| `consul.client.api.error.catalog_service_nodes.`         | Increments whenever a Consul agent receives an RPC error for request to list nodes offering a service.                                                                                                                                                                                                                                                                                                              | requests             | counter |
| `consul.client.rpc.error.catalog_service_nodes.`         | Increments whenever a Consul agent receives an RPC error for a request to list nodes offering a service.                                                                                                                                                                                                                                                                                                            | errors               | counter |
| `consul.client.api.catalog_node_services.`               | Increments whenever a Consul agent receives a request to list services registered in a node.                                                                                                                                                                                                                                                                                                                        | requests             | counter |
| `consul.client.api.success.catalog_node_services.`       | Increments whenever a Consul agent successfully responds to a request to list services in a node.                                                                                                                                                                                                                                                                                                                   | requests             | counter |
| `consul.client.rpc.error.catalog_node_services.`         | Increments whenever a Consul agent receives an RPC error for a request to list services in a node.                                                                                                                                                                                                                                                                                                                  | errors               | counter |
| `consul.client.api.catalog_node_service_list`            | Increments whenever a Consul agent receives a request to list a node's registered services.                                                                                                                                                                                                                                                                                                                         | requests             | counter |
| `consul.client.rpc.error.catalog_node_service_list`      | Increments whenever a Consul agent receives an RPC error for request to list a node's registered services.                                                                                                                                                                                                                                                                                                          | errors               | counter |
| `consul.client.api.success.catalog_node_service_list`    | Increments whenever a Consul agent successfully responds to a request to list a node's registered services.                                                                                                                                                                                                                                                                                                         | requests             | counter |
| `consul.client.api.catalog_gateway_services.`            | Increments whenever a Consul agent receives a request to list services associated with a gateway.                                                                                                                                                                                                                                                                                                                   | requests             | counter |
| `consul.client.api.success.catalog_gateway_services.`    | Increments whenever a Consul agent successfully responds to a request to list services associated with a gateway.                                                                                                                                                                                                                                                                                                   | requests             | counter |
| `consul.client.rpc.error.catalog_gateway_services.`      | Increments whenever a Consul agent receives an RPC error for a request to list services associated with a gateway.                                                                                                                                                                                                                                                                                                  | errors               | counter |
| `consul.runtime.num_goroutines`                          | Tracks the number of running goroutines and is a general load pressure indicator. This may burst from time to time but should return to a steady state value.                                                                                                                                                                                                                                                       | number of goroutines | gauge   |
| `consul.runtime.alloc_bytes`                             | Measures the number of bytes allocated by the Consul process. This may burst from time to time but should return to a steady state value.                                                                                                                                                                                                                                                                           | bytes                | gauge   |
| `consul.runtime.heap_objects`                            | Measures the number of objects allocated on the heap and is a general memory pressure indicator. This may burst from time to time but should return to a steady state value.                                                                                                                                                                                                                                        | number of objects    | gauge   |
| `consul.state.nodes`                                     | Measures the current number of nodes registered with Consul. It is only emitted by Consul servers. Added in v1.9.0.                                                                                                                                                                                                                                                                                                 | number of objects    | gauge   |
| `consul.state.services`                                  | Measures the current number of unique services registered with Consul, based on service name. It is only emitted by Consul servers. Added in v1.9.0.                                                                                                                                                                                                                                                                | number of objects    | gauge   |
| `consul.state.service_instances`                         | Measures the current number of unique service instances registered with Consul. It is only emitted by Consul servers. Added in v1.9.0.                                                                                                                                                                                                                                                                              | number of objects    | gauge   |
| `consul.state.kv_entries`                                | Measures the current number of unique KV entries written in Consul. It is only emitted by Consul servers. Added in v1.10.3.                                                                                                                                                                                                                                                                              | number of objects    | gauge   |
| `consul.state.connect_instances`                         | Measures the current number of unique connect service instances registered with Consul labeled by Kind (e.g. connect-proxy, connect-native, etc). Added in v1.10.4                                                                                                                                                                                                                                                  | number of objects    | gauge   |
| `consul.state.config_entries`                            | Measures the current number of configuration entries registered with Consul labeled by Kind (e.g. service-defaults, proxy-defaults, etc). See [Configuration Entries](/docs/connect/config-entries) for more information. Added in v1.10.4                                                                                                                                                                          | number of objects    | gauge   |
| `consul.members.clients`                                 | Measures the current number of client agents registered with Consul. It is only emitted by Consul servers. Added in v1.9.6.                                                                                                                                                                                                                                                                                         | number of clients    | gauge   |
| `consul.members.servers`                                 | Measures the current number of server agents registered with Consul. It is only emitted by Consul servers. Added in v1.9.6.                                                                                                                                                                                                                                                                                         | number of servers    | gauge   |
| `consul.dns.stale_queries`                               | Increments when an agent serves a query within the allowed stale threshold.                                                                                                                                                                                                                                                                                                                                         | queries              | counter |
| `consul.dns.ptr_query.`                                  | Measures the time spent handling a reverse DNS query for the given node.                                                                                                                                                                                                                                                                                                                                            | ms                   | timer   |
| `consul.dns.domain_query.`                               | Measures the time spent handling a domain query for the given node.                                                                                                                                                                                                                                                                                                                                                 | ms                   | timer   |
| `consul.http...`                                         | DEPRECATED IN 1.9: Tracks how long it takes to service the given HTTP request for the given verb and path. Paths do not include details like service or key names, for these an underscore will be present as a placeholder (eg. `consul.http.GET.v1.kv._`)                                                                                                                                                         | ms                   | timer   |
| `consul.system.licenseExpiration`                        | <EnterpriseAlert inline /> This measures the number of hours remaining on the agents license.                                                                                                                                                                                                                                                                                                                       | hours                | gauge   |
| `consul.version`                                         | Measures the count of running agents.                                                                                                                                                                                                                                                                                                                                                                               | agents               | gauge   |

## Server Health

These metrics are used to monitor the health of the Consul servers.

| Metric                                              | Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | Unit                              | Type    |
| --------------------------------------------------- |   | --------------------------------- | ------- |
| `consul.acl.apply`                                  | Measures the time it takes to complete an update to the ACL store.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | ms                                | timer   |
| `consul.acl.resolveTokenLegacy`                     | Measures the time it takes to resolve an ACL token using the legacy ACL system.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | ms                                | timer   |
| `consul.acl.ResolveToken`                           | Measures the time it takes to resolve an ACL token.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | ms                                | timer   |
| `consul.acl.ResolveTokenToIdentity`                 | Measures the time it takes to resolve an ACL token to an Identity.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | ms                                | timer   |
| `consul.acl.token.cache_hit`                        | Increments if Consul is able to resolve a token's identity, or a legacy token, from the cache.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | cache read op                     | counter |
| `consul.acl.token.cache_miss`                       | Increments if Consul cannot resolve a token's identity, or a legacy token, from the cache.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                | cache read op                     | counter |
| `consul.cache.bypass`                               | Counts how many times a request bypassed the cache because no cache-key was provided.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | counter                           | counter |
| `consul.cache.fetch_success`                        | Counts the number of successful fetches by the cache.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | counter                           | counter |
| `consul.cache.fetch_error`                          | Counts the number of failed fetches by the cache.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         | counter                           | counter |
| `consul.cache.evict_expired`                        | Counts the number of expired entries that are evicted.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | counter                           | counter |
| `consul.raft.applied_index`                         | Represents the raft applied index.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | index                             | gauge   |
| `consul.raft.apply`                                 | Counts the number of Raft transactions occurring over the interval, which is a general indicator of the write load on the Consul servers.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | raft transactions / interval      | counter |
| `consul.raft.barrier`                               | Counts the number of times the agent has started the barrier i.e the number of times it has issued a blocking call, to ensure that the agent has all the pending operations that were queued, to be applied to the agent's FSM.                                                                                                                                                                                                                                                                                                                                                                                                                               | blocks / interval                 | counter |
| `consul.raft.commitNumLogs`                         | Measures the count of logs processed for application to the FSM in a single batch.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | logs                              | gauge   |
| `consul.raft.commitTime`                            | Measures the time it takes to commit a new entry to the Raft log on the leader.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | ms                                | timer   |
| `consul.raft.fsm.lastRestoreDuration`               | Measures the time taken to restore the FSM from a snapshot on an agent restart or from the leader calling installSnapshot. This is a gauge that holds it's value since most servers only restore during restarts which are typically infrequent.                                                                                                                                                                                                                                                                                                                                                                                                              | ms                                | gauge   |
| `consul.raft.fsm.snapshot`                          | Measures the time taken by the FSM to record the current state for the snapshot.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | ms                                | timer   |
| `consul.raft.fsm.apply`                             | The number of logs committed since the last interval.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | commit logs / interval            | counter |
| `consul.raft.fsm.enqueue`                           | Measures the amount of time to enqueue a batch of logs for the FSM to apply.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | ms                                | timer   |
| `consul.raft.fsm.restore`                           | Measures the time taken by the FSM to restore its state from a snapshot.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | ms                                | timer   |
| `consul.raft.last_index`                            | Represents the raft applied index.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | index                             | gauge   |
| `consul.raft.leader.dispatchLog`                    | Measures the time it takes for the leader to write log entries to disk.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | ms                                | timer   |
| `consul.raft.leader.dispatchNumLogs`                | Measures the number of logs committed to disk in a batch.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | logs                              | gauge   |
| `consul.raft.leader.lastContact`                    | Measures the time since the leader was last able to contact the follower nodes when checking its leader lease. It can be used as a measure for how stable the Raft timing is and how close the leader is to timing out its lease.The lease timeout is 500 ms times the [`raft_multiplier` configuration](/docs/agent/options#raft_multiplier), so this telemetry value should not be getting close to that configured value, otherwise the Raft timing is marginal and might need to be tuned, or more powerful servers might be needed. See the [Server Performance](/docs/install/performance) guide for more details. | ms                                | timer   |
| `consul.raft.leader.oldestLogAge`                   | The number of milliseconds since the _oldest_ log in the leader's log store was written. This can be important for replication health where write rate is high and the snapshot is large as followers may be unable to recover from a restart if restoring takes longer than the minimum value for the current leader. Compare this with `consul.raft.fsm.lastRestoreDuration` and `consul.raft.rpc.installSnapshot` to monitor. In normal usage this gauge value will grow linearly over time until a snapshot completes on the leader and the log is truncated. Note: this metric won't be emitted until the leader writes a snapshot. After an upgrade to Consul 1.10.0 it won't be emitted until the oldest log was written after the upgrade. | ms                                | gauge   |
| `consul.raft.replication.heartbeat`                 | Measures the time taken to invoke appendEntries on a peer, so that it doesn’t timeout on a periodic basis.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | ms                                | timer   |
| `consul.raft.replication.appendEntries`             | Measures the time it takes to replicate log entries to followers. This is a general indicator of the load pressure on the Consul servers, as well as the performance of the communication between the servers.                                                                                                                                                                                                                                                                                                                                                                                                                                                       | ms                                | timer   |
| `consul.raft.replication.appendEntries.rpc`         | Measures the time taken by the append entries RFC, to replicate the log entries of a leader agent onto its follower agent(s)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | ms                                | timer   |
| `consul.raft.replication.appendEntries.logs`        | Measures the number of logs replicated to an agent, to bring it up to speed with the leader's logs.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | logs appended/ interval           | counter |
| `consul.raft.restore`                               | Counts the number of times the restore operation has been performed by the agent. Here, restore refers to the action of raft consuming an external snapshot to restore its state.                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | operation invoked / interval      | counter |
| `consul.raft.restoreUserSnapshot`                   | Measures the time taken by the agent to restore the FSM state from a user's snapshot                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | ms                                | timer   |
| `consul.raft.rpc.appendEntries`                     | Measures the time taken to process an append entries RPC call from an agent.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | ms                                | timer   |
| `consul.raft.rpc.appendEntries.storeLogs`           | Measures the time taken to add any outstanding logs for an agent, since the last appendEntries was invoked                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | ms                                | timer   |
| `consul.raft.rpc.appendEntries.processLogs`         | Measures the time taken to process the outstanding log entries of an agent.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | ms                                | timer   |
| `consul.raft.rpc.installSnapshot`                   | Measures the time taken to process the installSnapshot RPC call. This metric should only be seen on agents which are currently in the follower state.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         | ms                                | timer   |
| `consul.raft.rpc.processHeartBeat`                  | Measures the time taken to process a heartbeat request.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | ms                                | timer   |
| `consul.raft.rpc.requestVote`                       | Measures the time taken to process the request vote RPC call.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | ms                                | timer   |
| `consul.raft.snapshot.create`                       | Measures the time taken to initialize the snapshot process.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | ms                                | timer   |
| `consul.raft.snapshot.persist`                      | Measures the time taken to dump the current snapshot taken by the Consul agent to the disk.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | ms                                | timer   |
| `consul.raft.snapshot.takeSnapshot`                 | Measures the total time involved in taking the current snapshot (creating one and persisting it) by the Consul agent.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         | ms                                | timer   |
| `consul.serf.snapshot.appendLine`                   | Measures the time taken by the Consul agent to append an entry into the existing log.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         | ms                                | timer   |
| `consul.serf.snapshot.compact`                      | Measures the time taken by the Consul agent to compact a log. This operation occurs only when the snapshot becomes large enough to justify the compaction .                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | ms                                | timer   |
| `consul.raft.state.candidate`                       | Increments whenever a Consul server starts an election. If this increments without a leadership change occurring it could indicate that a single server is overloaded or is experiencing network connectivity issues.                                                                                                                                                                                                                                                                                                                                                                                                                                                | election attempts / interval      | counter |
| `consul.raft.state.leader`                          | Increments whenever a Consul server becomes a leader. If there are frequent leadership changes this may be indication that the servers are overloaded and aren't meeting the soft real-time requirements for Raft, or that there are networking problems between the servers.                                                                                                                                                                                                                                                                                                                                                                                        | leadership transitions / interval | counter |
| `consul.raft.state.follower`                        | Counts the number of times an agent has entered the follower mode. This happens when a new agent joins the cluster or after the end of a leader election.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | follower state entered / interval | counter |
| `consul.raft.transition.heartbeat_timeout`         | The number of times an agent has transitioned to the Candidate state, after receive no heartbeat messages from the last known leader.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | timeouts / interval               | counter |
| `consul.raft.verify_leader`                         | Counts the number of times an agent checks whether it is still the leader or not                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | checks / interval                 | Counter |
| `consul.rpc.accept_conn`                            | Increments when a server accepts an RPC connection.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | connections                       | counter |
| `consul.catalog.register`                           | Measures the time it takes to complete a catalog register operation.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | ms                                | timer   |
| `consul.catalog.deregister`                         | Measures the time it takes to complete a catalog deregister operation.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | ms                                | timer   |
| `consul.fsm.register`                               | Measures the time it takes to apply a catalog register operation to the FSM.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         | ms                                | timer   |
| `consul.fsm.deregister`                             | Measures the time it takes to apply a catalog deregister operation to the FSM.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | ms                                | timer   |
| `consul.fsm.acl.`                                   | Measures the time it takes to apply the given ACL operation to the FSM.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | ms                                | timer   |
| `consul.fsm.session.`                               | Measures the time it takes to apply the given session operation to the FSM.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | ms                                | timer   |
| `consul.fsm.kvs.`                                   | Measures the time it takes to apply the given KV operation to the FSM.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | ms                                | timer   |
| `consul.fsm.tombstone.`                             | Measures the time it takes to apply the given tombstone operation to the FSM.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | ms                                | timer   |
| `consul.fsm.coordinate.batch-update`                | Measures the time it takes to apply the given batch coordinate update to the FSM.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | ms                                | timer   |
| `consul.fsm.prepared-query.`                        | Measures the time it takes to apply the given prepared query update operation to the FSM.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | ms                                | timer   |
| `consul.fsm.txn`                                    | Measures the time it takes to apply the given transaction update to the FSM.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         | ms                                | timer   |
| `consul.fsm.autopilot`                              | Measures the time it takes to apply the given autopilot update to the FSM.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | ms                                | timer   |
| `consul.fsm.persist`                                | Measures the time it takes to persist the FSM to a raft snapshot.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | ms                                | timer   |
| `consul.fsm.intention`                              | Measures the time it takes to apply an intention operation to the state store.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | ms                                | timer   |
| `consul.fsm.ca`                                     | Measures the time it takes to apply CA configuration operations to the FSM.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | ms                                | timer   |
| `consul.fsm.ca.leaf`                                | Measures the time it takes to apply an operation while signing a leaf certificate.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | ms                                | timer   |
| `consul.fsm.acl.token`                              | Measures the time it takes to apply an ACL token operation to the FSM.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | ms                                | timer   |
| `consul.fsm.acl.policy`                             | Measures the time it takes to apply an ACL policy operation to the FSM.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | ms                                | timer   |
| `consul.fsm.acl.bindingrule`                        | Measures the time it takes to apply an ACL binding rule operation to the FSM.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | ms                                | timer   |
| `consul.fsm.acl.authmethod`                         | Measures the time it takes to apply an ACL authmethod operation to the FSM.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | ms                                | timer   |
| `consul.fsm.system_metadata`                        | Measures the time it takes to apply a system metadata operation to the FSM.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | ms                                | timer   |
| `consul.kvs.apply`                                  | Measures the time it takes to complete an update to the KV store.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | ms                                | timer   |
| `consul.leader.barrier`                             | Measures the time spent waiting for the raft barrier upon gaining leadership.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | ms                                | timer   |
| `consul.leader.reconcile`                           | Measures the time spent updating the raft store from the serf member information.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | ms                                | timer   |
| `consul.leader.reconcileMember`                     | Measures the time spent updating the raft store for a single serf member's information.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | ms                                | timer   |
| `consul.leader.reapTombstones`                      | Measures the time spent clearing tombstones.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         | ms                                | timer   |
| `consul.leader.replication.acl-policies.status`     | This will only be emitted by the leader in a secondary datacenter. The value will be a 1 if the last round of ACL policy replication was successful or 0 if there was an error. | healthy | gauge |
| `consul.leader.replication.acl-policies.index`      | This will only be emitted by the leader in a secondary datacenter. Increments to the index of ACL policies in the primary datacenter that have been successfully replicated. | index | gauge |
| `consul.leader.replication.acl-roles.status`        | This will only be emitted by the leader in a secondary datacenter. The value will be a 1 if the last round of ACL role replication was successful or 0 if there was an error. | healthy | gauge |
| `consul.leader.replication.acl-roles.index`         | This will only be emitted by the leader in a secondary datacenter. Increments to the index of ACL roles in the primary datacenter that have been successfully replicated. | index | gauge |
| `consul.leader.replication.acl-tokens.status`       | This will only be emitted by the leader in a secondary datacenter. The value will be a 1 if the last round of ACL token replication was successful or 0 if there was an error. | healthy | gauge |
| `consul.leader.replication.acl-tokens.index`        | This will only be emitted by the leader in a secondary datacenter. Increments to the index of ACL tokens in the primary datacenter that have been successfully replicated. | index | gauge |
| `consul.leader.replication.config-entries.status`   | This will only be emitted by the leader in a secondary datacenter. The value will be a 1 if the last round of config entry replication was successful or 0 if there was an error. | healthy | gauge |
| `consul.leader.replication.config-entries.index`    | This will only be emitted by the leader in a secondary datacenter. Increments to the index of config entries in the primary datacenter that have been successfully replicated. | index | gauge |
| `consul.leader.replication.federation-state.status` | This will only be emitted by the leader in a secondary datacenter. The value will be a 1 if the last round of federation state replication was successful or 0 if there was an error. | healthy | gauge |
| `consul.leader.replication.federation-state.index`  | This will only be emitted by the leader in a secondary datacenter. Increments to the index of federation states in the primary datacenter that have been successfully replicated. | index | gauge |
| `consul.leader.replication.namespaces.status`       | <EnterpriseAlert inline /> This will only be emitted by the leader in a secondary datacenter. The value will be a 1 if the last round of namespace replication was successful or 0 if there was an error. | healthy | gauge |
| `consul.leader.replication.namespaces.index`        | <EnterpriseAlert inline /> This will only be emitted by the leader in a secondary datacenter. Increments to the index of namespaces in the primary datacenter that have been successfully replicated. | index | gauge |
| `consul.prepared-query.apply`                       | Measures the time it takes to apply a prepared query update.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         | ms                                | timer   |
| `consul.prepared-query.explain`                     | Measures the time it takes to process a prepared query explain request.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | ms                                | timer   |
| `consul.prepared-query.execute`                     | Measures the time it takes to process a prepared query execute request.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | ms                                | timer   |
| `consul.prepared-query.execute_remote`              | Measures the time it takes to process a prepared query execute request that was forwarded to another datacenter.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | ms                                | timer   |
| `consul.rpc.raft_handoff`                           | Increments when a server accepts a Raft-related RPC connection.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | connections                       | counter |
| `consul.rpc.request_error`                          | Increments when a server returns an error from an RPC request.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | errors                            | counter |
| `consul.rpc.request`                                | Increments when a server receives a Consul-related RPC request.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | requests                          | counter |
| `consul.rpc.query`                                  | Increments when a server receives a read RPC request, indicating the rate of new read queries. See consul.rpc.queries_blocking for the current number of in-flight blocking RPC calls. This metric changed in 1.7.0 to only increment on the the start of a query. The rate of queries will appear lower, but is more accurate.                                                                                                                                                                                                                                                                                                                      | queries                           | counter |
| `consul.rpc.queries_blocking`                       | The current number of in-flight blocking queries the server is handling.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | queries                           | gauge   |
| `consul.rpc.cross-dc`                               | Increments when a server sends a (potentially blocking) cross datacenter RPC query.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | queries                           | counter |
| `consul.rpc.consistentRead`                         | Measures the time spent confirming that a consistent read can be performed.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | ms                                | timer   |
| `consul.session.apply`                              | Measures the time spent applying a session update.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | ms                                | timer   |
| `consul.session.renew`                              | Measures the time spent renewing a session.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | ms                                | timer   |
| `consul.session_ttl.invalidate`                     | Measures the time spent invalidating an expired session.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | ms                                | timer   |
| `consul.txn.apply`                                  | Measures the time spent applying a transaction operation.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | ms                                | timer   |
| `consul.txn.read`                                   | Measures the time spent returning a read transaction.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                | ms                                | timer   |
| `consul.grpc.client.request.count`                  | Counts the number of gRPC requests made by the client agent to a Consul server.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | requests                          | counter |
| `consul.grpc.client.connection.count`               | Counts the number of new gRPC connections opened by the client agent to a Consul server.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | connections                       | counter |
| `consul.grpc.client.connections`                    | Measures the number of active gRPC connections open from the client agent to any Consul servers.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | connections                       | gauge   |
| `consul.grpc.server.request.count`                  | Counts the number of gRPC requests received by the server.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | requests                          | counter |
| `consul.grpc.server.connection.count`               | Counts the number of new gRPC connections received by the server.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | connections                       | counter |
| `consul.grpc.server.connections`                    | Measures the number of active gRPC connections open on the server.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | connections                       | gauge   |
| `consul.grpc.server.stream.count`                   | Counts the number of new gRPC streams received by the server.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | streams                           | counter |
| `consul.grpc.server.streams`                        | Measures the number of active gRPC streams handled by the server.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | streams                           | gauge   |
| `consul.xds.server.streams`                         | Measures the number of active xDS streams handled by the server split by protocol version.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | streams                           | gauge   |

## Cluster Health

These metrics give insight into the health of the cluster as a whole.

| Metric                                | Description                                                                                                                                                                                                                                                                                                                                                                                                                                    | Unit                                    | Type    |
| ------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------- | ------- |
| `consul.memberlist.degraded.probe`    | Counts the number of times the agent has performed failure detection on another agent at a slower probe rate. The agent uses its own health metric as an indicator to perform this action. (If its health score is low, means that the node is healthy, and vice versa.)                                                                                                                                                           | probes / interval                       | counter |
| `consul.memberlist.degraded.timeout`  | Counts the number of times an agent was marked as a dead node, whilst not getting enough confirmations from a randomly selected list of agent nodes in an agent's membership.                                                                                                                                                                                                                                                      | occurrence / interval                   | counter |
| `consul.memberlist.msg.dead`          | Counts the number of times an agent has marked another agent to be a dead node.                                                                                                                                                                                                                                                                                                                                                    | messages / interval                     | counter |
| `consul.memberlist.health.score`      | Describes a node's perception of its own health based on how well it is meeting the soft real-time requirements of the protocol. This metric ranges from 0 to 8, where 0 indicates "totally healthy". This health score is used to scale the time between outgoing probes, and higher scores translate into longer probing intervals. For more details see section IV of the Lifeguard paper: https://arxiv.org/pdf/1707.00788.pdf | score                                   | gauge   |
| `consul.memberlist.msg.suspect`       | Increments when an agent suspects another as failed when executing random probes as part of the gossip protocol. These can be an indicator of overloaded agents, network problems, or configuration errors where agents can not connect to each other on the [required ports](/docs/agent/options#ports).                                                                                                                                 | suspect messages received / interval    | counter |
| `consul.memberlist.tcp.accept`        | Counts the number of times an agent has accepted an incoming TCP stream connection.                                                                                                                                                                                                                                                                                                                                                | connections accepted / interval         | counter |
| `consul.memberlist.udp.sent/received` | Measures the total number of bytes sent/received by an agent through the UDP protocol.                                                                                                                                                                                                                                                                                                                                             | bytes sent or bytes received / interval | counter |
| `consul.memberlist.tcp.connect`       | Counts the number of times an agent has initiated a push/pull sync with an other agent.                                                                                                                                                                                                                                                                                                                                            | push/pull initiated / interval          | counter |
| `consul.memberlist.tcp.sent`          | Measures the total number of bytes sent by an agent through the TCP protocol                                                                                                                                                                                                                                                                                                                                                       | bytes sent / interval                   | counter |
| `consul.memberlist.gossip`            | Measures the time taken for gossip messages to be broadcasted to a set of randomly selected nodes.                                                                                                                                                                                                                                                                                                                                 | ms                  | timer |
| `consul.memberlist.msg_alive`         | Counts the number of alive messages, that the agent has processed so far, based on the message information given by the network layer.                                                                                                                                                                                                                                                                                              | messages / Interval                        | counter |
| `consul.memberlist.msg_dead`          | The number of dead messages that the agent has processed so far, based on the message information given by the network layer.                                                                                                                                                                                                                                                                                                | messages / Interval                        | counter |
| `consul.memberlist.msg_suspect`       | The number of suspect messages that the agent has processed so far, based on the message information given by the network layer.                                                                                                                                                                                                                                                                                              | messages / Interval                        | counter |
| `consul.memberlist.probeNode`         | Measures the time taken to perform a single round of failure detection on a select agent.                                                                                                                                                                                                                                                                                                                                          | nodes / Interval                        | counter |
| `consul.memberlist.pushPullNode`      | Measures the number of agents that have exchanged state with this agent.                                                                                                                                                                                                                                                                                                                                                           | nodes / Interval                        | counter |
| `consul.serf.member.failed`           | Increments when an agent is marked dead. This can be an indicator of overloaded agents, network problems, or configuration errors where agents cannot connect to each other on the [required ports](/docs/agent/options#ports).                                                                                                                                                                                                           | failures / interval                     | counter |
| `consul.serf.member.flap`             | Available in Consul 0.7 and later, this increments when an agent is marked dead and then recovers within a short time period. This can be an indicator of overloaded agents, network problems, or configuration errors where agents cannot connect to each other on the [required ports](/docs/agent/options#ports).                                                                                                                           | flaps / interval                        | counter |
| `consul.serf.member.join`             | Increments when an agent joins the cluster. If an agent flapped or failed this counter also increments when it re-joins.                                                                                                                                                                                                                                                                                                                  | joins / interval                        | counter |
| `consul.serf.member.left`             | Increments when an agent leaves the cluster.                                                                                                                                                                                                                                                                                                                                                                                              | leaves / interval                       | counter |
| `consul.serf.events`                  | Increments when an agent processes an [event](/commands/event). Consul uses events internally so there may be additional events showing in telemetry. There are also a per-event counters emitted as `consul.serf.events.`.                                                                                                                                                                                                               | events / interval                       | counter |
| `consul.serf.msgs.sent`               | This metric is sample of the number of bytes of messages broadcast to the cluster. In a given time interval, the sum of this metric is the total number of bytes sent and the count is the number of messages sent.                                                                                                                                                                                                                            | message bytes / interval                | counter |
| `consul.autopilot.failure_tolerance`  | Tracks the number of voting servers that the cluster can lose while continuing to function.                                                                                                                                                                                                                                                                                                                                               | servers                                 | gauge   |
| `consul.autopilot.healthy`            | Tracks the overall health of the local server cluster. If all servers are considered healthy by Autopilot, this will be set to 1. If any are unhealthy, this will be 0. All non-leader servers will report `NaN`.                                                                                                                                                                                                                                                                   | boolean                                 | gauge   |
| `consul.session_ttl.active`           | Tracks the active number of sessions being tracked.                                                                                                                                                                                                                                                                                                                                                                                       | sessions                                | gauge   |
| `consul.catalog.service.query.`       | Increments for each catalog query for the given service.                                                                                                                                                                                                                                                                                                                                                                                  | queries                                 | counter |
| `consul.catalog.service.query-tag..`  | Increments for each catalog query for the given service with the given tag.                                                                                                                                                                                                                                                                                                                                                               | queries                                 | counter |
| `consul.catalog.service.query-tags..` | Increments for each catalog query for the given service with the given tags.                                                                                                                                                                                                                                                                                                                                                              | queries                                 | counter |
| `consul.catalog.service.not-found.`   | Increments for each catalog query where the given service could not be found.                                                                                                                                                                                                                                                                                                                                                             | queries                                 | counter |
| `consul.catalog.connect.query.`       | Increments for each connect-based catalog query for the given service.                                                                                                                                                                                                                                                                                                                                                                    | queries                                 | counter |
| `consul.catalog.connect.query-tag..`  | Increments for each connect-based catalog query for the given service with the given tag.                                                                                                                                                                                                                                                                                                                                                 | queries                                 | counter |
| `consul.catalog.connect.query-tags..` | Increments for each connect-based catalog query for the given service with the given tags.                                                                                                                                                                                                                                                                                                                                                | queries                                 | counter |
| `consul.catalog.connect.not-found.`   | Increments for each connect-based catalog query where the given service could not be found.                                                                                                                                                                                                                                                                                                                                               | queries                                 | counter |

## Connect Built-in Proxy Metrics

Consul Connect's built-in proxy is by default configured to log metrics to the
same sink as the agent that starts it.

When running in this mode it emits some basic metrics. These will be expanded
upon in the future.

All metrics are prefixed with `consul.proxy.<proxied-service-id>` to distinguish
between multiple proxies on a given host. The table below use `web` as an
example service name for brevity.

### Labels

Most labels have a `dst` label and some have a `src` label. When using metrics
sinks and timeseries stores that support labels or tags, these allow aggregating
the connections by service name.

Assuming all services are using a managed built-in proxy, you can get a complete
overview of both number of open connections and bytes sent and received between
all services by aggregating over these metrics.

For example aggregating over all `upstream` (i.e. outbound) connections which
have both `src` and `dst` labels, you can get a sum of all the bandwidth in and
out of a given service or the total number of connections between two services.

### Metrics Reference

The standard go runtime metrics are exported by `go-metrics` as with Consul
agent. The table below describes the additional metrics exported by the proxy.

| Metric                              | Description                                                                                                                                                                                                                                                       | Unit        | Type    |
| ----------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------- | ------- |
| `consul.proxy.web.runtime.*`        | The same go runtime metrics as documented for the agent above.                                                                                                                                                                                                    | mixed       | mixed   |
| `consul.proxy.web.inbound.conns`    | Shows the current number of connections open from inbound requests to the proxy. Where supported a `dst` label is added indicating the service name the proxy represents.                                                                                         | connections | gauge   |
| `consul.proxy.web.inbound.rx_bytes` | Increments by the number of bytes received from an inbound client connection. Where supported a `dst` label is added indicating the service name the proxy represents.                                                                                       | bytes       | counter |
| `consul.proxy.web.inbound.tx_bytes` | Increments by the number of bytes transferred to an inbound client connection. Where supported a `dst` label is added indicating the service name the proxy represents.                                                                                      | bytes       | counter |
| `consul.proxy.web.upstream.conns`   | Shows the current number of connections open from a proxy instance to an upstream. Where supported a `src` label is added indicating the service name the proxy represents, and a `dst` label is added indicating the service name the upstream is connecting to. | connections | gauge   |
| `consul.proxy.web.inbound.rx_bytes` | Increments by the number of bytes received from an upstream connection. Where supported a `src` label is added indicating the service name the proxy represents, and a `dst` label is added indicating the service name the upstream is connecting to.       | bytes       | counter |
| `consul.proxy.web.inbound.tx_bytes` | Increments by the number of bytes transferred to an upstream connection. Where supported a `src` label is added indicating the service name the proxy represents, and a `dst` label is added indicating the service name the upstream is connecting to.      | bytes       | counter |
