What is LAVA?
*************

* LAVA is the Linaro Automation and Validation Architecture.

* LAVA is a :ref:`continuous integration <continuous_integration>` system for
  deploying operating systems onto physical and virtual hardware for running
  tests. Tests can be simple boot testing, bootloader testing and system level
  testing, although extra hardware may be required for some system tests.
  Results are tracked over time and data can be exported for further analysis.

* LAVA is a collection of participating components in an evolving architecture.
  LAVA aims to make systematic, automatic and manual quality control more
  approachable for projects of all sizes.

* LAVA is designed for validation during development - testing whether the code
  that engineers are producing "works", in whatever sense that means. Depending
  on context, this could be many things, for example:

  * testing whether changes in the Linux kernel compile and boot

  * testing whether the code produced by gcc is smaller or faster

  * testing whether a kernel scheduler change reduces power consumption for a
    certain workload

  * etc.

* LAVA is good for automated validation. LAVA tests the Linux kernel on a range
  of supported boards every day. LAVA tests proposed android changes in gerrit
  before they are landed, and does the same for other projects like gcc. Linaro
  runs a central validation lab in Cambridge, containing racks full of
  computers supplied by Linaro members and the necessary infrastucture to
  control them (servers, serial console servers, network switches etc.)

* LAVA is good for providing developers with the ability to run customised test
  on a variety of different types of hardware, some of which may be difficult
  to obtain or integrate. Although LAVA has support for emulation (based on
  QEMU), LAVA is best at providing test support for real hardware devices.

* LAVA is principally aimed at testing changes made by developers across
  multiple hardware platforms to aid portability and encourage multi-platform
  development. Systems which are already platform independent or which have
  been optimised for production may not necessarily be able to be tested in
  LAVA or may provide no overall gain.

.. note:: This overview document explains LAVA using
   http://validation.linaro.org/ which is the official production instance of
   LAVA hosted by Linaro. Where examples reference ``validation.linaro.org``,
   replace with the fully qualified domain name of your LAVA instance.

.. _what_is_lava_not:

What is LAVA **not**?
*********************

* LAVA is **not** a set of tests - it is infrastructure to enable
  users to run their own tests. LAVA concentrates on providing a range of
  deployment methods and a range of boot methods. Once the login is complete,
  the test consists of whatever scripts the test writer chooses to execute in
  that environment.

* LAVA is **not** a test lab - it is the software that can used in a test lab
  to control test devices.

* LAVA is **not** a complete :abbr:`CI (continuous integration)` system -  it
  is software that can form part of a CI loop. LAVA supports data extraction to
  make it easier to produce a frontend which is directly relevant to particular
  groups of developers.

* LAVA is **not** a build farm - other tools need to be used to prepare
  binaries which can be passed to the device using LAVA.

* LAVA is **not** a production test environment for hardware - LAVA is focused
  on developers and may require changes to the device or the software to enable
  automation. These changes are often unsuitable for production units. LAVA
  also expects that most devices will remain available for repeated testing
  rather than testing the software with a changing set of hardware.

.. seealso:: :ref:`continuous_integration` which covers how LAVA relates to
   continuous integration (CI) and covers the consequences of what LAVA can and
   cannot do with particular emphasis on how automation itself can block some
   forms of testing.

Features
********

* **Automated validation** - designed for automated processes to create,
  submit and process results of test jobs to validate the development
  process.

* **Parallel scheduling** - multiple test jobs run at the same time
  across multiple devices.

* **MultiNode test jobs** - test jobs can be run as a single group of
  tests involving multiple devices.

* **Hardware sharing** - uncommon hardware is shared between disparate
  groups to maximise usage

* **Wide device coverage** - a large number of types of device can be
  supported with instances ranging from one to more than a hundred
  devices available for test jobs.

* **Data export for customisation** - transform the data using custom
  interfaces to make the validation output directly relevant to specific
  teams.

* **Privacy support** - test jobs or types of device can be kept private
  to selected groups, individuals or teams.

* **Live result reporting** - if a test job does fail, all results
  up to the point of failure are retained.

* **UNIX and Android test support** - Test jobs can be run on systems
  running various UNIX flavours or using the Android Debug Bridge to
  interface with mobile devices.

* **Complex network testing** - reconfigurable networking across multiple
  devices using multiple network interfaces.
