Developing LAVA on Debian¶
LAVA no longer supports development on Ubuntu.
Packages for LAVA are available for:
Debian Buster (testing)
Debian Sid (unstable)
When using the packages to develop LAVA, there is a change to the workflow compared to the old lava-deployment-tool buildouts.
Changes to build dependencies between Debian versions can cause changes to the builds for each suite. Always ensure that you build packages for unstable using unstable and build packages for stable using a chroot or VM or other stable environment. If a package built on unstable does not install on stable, rebuild the same changes in a stable environment and re-install. Backports to stable in Debian are always built in a stable chroot or VM for this reason.
In the very early stages, LAVA was deployed using a custom script based on PyPi and a lot of manual effort. This deployment tool frequently failed in complex and unexpected ways. It become clear that this would block successful and reliable deployment and upgrades of LAVA, particularly in larger scale environments.
The main LAVA developer at the time was also a Debian developer with the rights and familiarity with Debian to convert the deployment tool into a packaged format which solved these issues.
LAVA is not inherently tied to Debian but following the route of packaging LAVA in Debian solved many issues very easily. By using a well supported and readily understood distribution as our base, many users have been able to install and operate LAVA without needing direct help from the developers. We have also gained a stable and reliable platform for our internal CI which was an enormous aid during the V2 development cycle.
Whilst it might seem that lots of developer time is spent doing Debian specific development, equivalent (and possibly more) work would be needed to develop and support LAVA on any platform. Debian provides a very large collection of packaged software, removing the need for us to package and maintain the full stack which LAVA needs.
Options for other distributions¶
Although LAVA is not inherently tied to the Debian distribution, there would be some work involved to ensure that another method of deploying LAVA would work well enough for the upstream LAVA team to officially support that method.
On top of developing LAVA itself, full support of LAVA in Debian includes:
Maintenance of packaging code, either upstream or in a public git repository.
Preparation of LAVA releases for inclusion into the distribution.
Rights to upload LAVA releases to the distribution and access within the distribution to apply local patches, upload security fixes and provide for backporting newer dependencies to maintain support for existing releases.
Maintenance of a LAVA lab using this distribution and running CI on LAVA devices. (This is to ensure that the functionality of LAVA is being tested on this distribution. It would be very useful, for example. for such a lab to participate in functional testing of LAVA upstream.)
Sufficient involvement in the distribution and familiarity with the distribution release process to provide full support for both installing new instances and smoothly upgrading established instances to each new release of the distribution.
This includes planning ahead to ensure that new dependencies are packaged for the distribution in time for the next distribution release.
Maintenance of LAVA releases within the distribution across more than one distribution release cycle, at the same time.
This is to ensure that users have continuity of support and can choose when to migrate the base operating system of their labs.
Involvement on IRC and mailing lists to promptly support users experiencing problems with using LAVA on the distribution.
Maintenance of the LAVA documentation covering how to use LAVA on the distribution.
Triage and fixing of issues in LAVA which are specific to the distribution.
Discussion with the rest of LAVA Software Community Project development team around issues related to this distribution.
Use of all available tools within the distribution to anticipate problems. Where possible, implementation of fixes before users are affected.
Maintenance of dependencies using
./share/requires.pyto enable automated testing. This includes testing the versions of specific dependencies and ensuring that the minimum version is available in all supported releases of the distribution.
Maintenance of scripts which build Docker images for and using that distribution, including publishing such images. These images will be required to support the internal CI.
Maintenance of upstream LAVA CI using that distribution in Docker to run the unit tests as well as build and test the packaging of LAVA for that distribution. This CI will involve, at a minimum, running such tests on the currently supported distribution release and the candidate for the next distribution release.
Maintenance of upstream CI using
gitlab-runneron a machine running the relevant distribution so that CI jobs on the new distribution run in parallel to the CI jobs running on Debian.
Maintenance of LAVA tools and support scripts for running a LAVA lab using the distribution.
Consideration that support for the distribution may involve supporting more than one system architecture.
As an example from LAVA’s history, support for migrations between releases was the main problem for LAVA support of Ubuntu. It became impossible to provide a smooth upgrade path from one Ubuntu LTS release (14.04 Trusty) to the next LTS release (16.04 Xenial). LAVA needs to provide long term stability to provide reliable CI whilst keeping up with changes across supported distributions and tools. For the sake of lab admin workload, support needs to concentrate on LTS or server level releases rather than developer releases or interim updates. Even though Ubuntu is closely related to Debian, the timing of Ubuntu releases made it very difficult to manage complex transitions like the change from Django 1.4 to 1.8 and this was also a concern for the transition to Python3.
You may find that more than one person will be required to meet all these criteria and to maintain that support across several releases of the distribution. The current LAVA Software Community Project team does not have enough resources to do this work for any distribution other than Debian.
Talk to us before spending time on such work.
Preparing for LAVA development¶
LAVA provides a
lava-dev package which supplies all the dependencies which
are required to build local LAVA packages. This package is
intended primarily for developers working on laptops and other systems where
a full desktop environment is already installed:
$ sudo apt install lava-dev
If you want to build local packages on a headless box or a system with limited
space, you can trim the set of dependencies by pre-installing
pinentry-curses instead of the default
pinentry-gtk2. QEMU is still
required and will bring in some X11 dependencies but these are minimal compared
to the full dependencies of
pinentry-gtk2 which is brought in via
$ sudo apt install pinentry-curses $ sudo apt-get --purge remove pinentry-gtk2 $ sudo apt-get --purge autoremove $ sudo apt install lava-dev
Developer package build¶
The supported suite for LAVA development is now Buster. The
developer package build now defaults to expecting Buster and
therefore uses Python3 exclusively. Support for building Python2 has
been removed, the
master branch only builds Python3. See
lava-dev package includes a helper script which is also present
in the source code in
lava-server/share/. The script requires a
normal Debian package build environment (i.e.
git-buildpackage helper and the build-dependencies of the package
itself. The helper checks for package dependencies using
dpkg-checkbuilddeps which halts upon failure with a message showing
which packages need to be installed.
Changes from 2018.10 onwards¶
the Debian packaging files are now included upstream, so merge requests can include changes to the packaging directly. The helper script converts the package to a “native” package to allow for unreleased changes.
ALL local changes must be committed to a local branch before attempting a build - the helper will fail with an error if
git ls-files -m -o --exclude-standardreports any output.
Builds are executed in a temporary scratch branch called
lavadevscratchwhich is based on the current local branch and which is deleted at the end of the operation. This is required so that the packaging can be temporarily switched to a developer build.
The helper script no longer accepts the
-poption, the name of the package is determined from the upstream Debian packaging.
The helper script not longer accepts the
-boption to change the packaging branch as the packaging is now part of the same branch as the build.
From time to time, dependencies may need to vary between the current Debian
stable release and the unstable suite and the package building tools expect
to build for unstable. If you are building a package to update an instance
running a different suite, pass that suite using the
$ ./share/debian-dev-build.sh -s buster
By default, the packages will be built in the
directory, this can be changed with the
-o option. Packages are
build using a version string based on the output of
except that hyphens
- are replaced with period
. to comply with
the rules for a native Debian package. The helper script outputs the
relative location of all the files generated by the build at the end of
a successful build, ready for use with
$ sudo dpkg -i
<path_to_dot_deb_file>, repeated for every file or
$ sudo debi -u
<path_to_lava_dot_changes_file> which will upgrade matching packages
which are already installed but skip ones which are not installed.
$ sudo dpkg -i ../build-area/lava-common_2018.7-15-g64824c402-1_all.deb $ sudo dpkg -i ../build-area/lava-dispatcher_2018.7-15-g64824c402-1_amd64.deb ...
or all in one command:
$ sudo debi -u ../build-area/lava_2018.7-15-g64824c402-1_amd64.changes
To install any package, including the developer build packages, the corresponding package must already be installed at the current production release version (or better), on the same machine. This ensures that all of the runtime dependencies already exist on the system.
Which branch to use for changes¶
Any and all changes for inclusion into a future release need to be based on the current git master branch and will need rebasing from time to time as master moves ahead.
All testing of the LAVA source code is based on the relevant master branch which is then merged into the staging branch for testing as a release candidate. The final release involves merging staging into the release branch. Git tags are based on the release branch.
When using existing git tags or the release branch, create a new local branch and commit your changes to ensure that a local version string is used.
There can also be new dependencies added by changes in master and staging before those changes are merged into release or uploaded as a production release. When these changes are merged into master, the packaging will also be updated.
Local version strings¶
The local version is built (using
./lava_common/version.py) from these components:
git describe- (dashes replaced by dots):
$ ./lava_common/version.py 2018.7.35.gb022cde9
The latest git hash is a reference to the latest commit. If you have
not committed local changes (e.g. you are on a local branch based on a
tag) then the short hash can be used to lookup the commit in the master
branch, omitting the
g prefix, e.g.:
Always build packages on the suite you expect to use for installation.
The helper supports
$ sudo apt install lava-dev $ git clone https://git.lavasoftware.org/lava/lava.git $ cd lava $ ./share/debian-dev-build.sh
lava-dispatcher has architecture-dependent dependencies. By
default, the package is built for the native architecture and can only
be installed on that architecture. To build for a different
architecture, e.g. arm64, use:
$ /usr/share/lava-server/debian-dev-build.sh -a arm64 -B
This does a binary build, so the source is not included, which allows
these builds to be included in a local repository, e.g. using
Helpers for other distributions may be added in due course. Patches welcome.
Developer build versions¶
LAVA uses git tags and the developer build adds a suffix to the tag for
each local build - the suffix is formed from the output of
Local version strings for information on how to look up the commit information from the version string.
From August 2015, LAVA uses git tags without a leading zero on the
month number, in accordance with PEP440, so the git tag will be
2015.8 instead of
2015.07 used for the previous release tag.
Development using Python3¶
LAVA has moved to exclusive Python3 support as the final stage of the migration to V2. See https://lists.lavasoftware.org/pipermail/lava-announce/2017-June/000032.html
Both lava-server and lava-dispatcher only support running the unit tests with Python3. All reviews must pass the unit tests when run with Python3.
Builds for Debian Jessie have ceased, support for Python2 has been dropped and only Python3 is be supported.
Python3 and other dependencies are tracked using files in
share/requirements using the
Required arguments are:
-d, --distribution Name of a distribution directory in ./share/requirements -s, --suite Name of a suite in the specified distribution directory -p, --package A LAVA package name in the distribution and suite
Optional arguments are:
-n, --names List the distribution package names -u, --unittests Distribution package names for unittest support - requires --names
./share/requires.py --distribution debian --suite buster --package lava-dispatcher --names python3-configobj python3-guestfs python3-jinja2 python3-magic python3-netifaces python3-pexpect python3-pyudev python3-requests python3-setproctitle python3-tz python3-yaml python3-zmq
Quick fixes and testing¶
The paths to execute LAVA python scripts and run unit tests have changed and developing LAVA based on packages has a different workflow.
Modified files can be copied to the equivalent python path. The current LAVA
packages use python3, so the path is beneath
/usr/lib/python3/dist-packages/ with sudo:
$ sudo cp <git-path> /usr/lib/python3/dist-packages/<git-path>
Different actions are needed for local changes to take effect, depending on the type of file(s) updated:
next browser refresh (F5/Ctrl-R)
next testjob submission
next testjob submission
Migrating postgresql versions¶
LAVA installs the
postgresql package which installs the current default
version of postgresql. When this default changes in Debian, a second package
will be added to your system which will start with no actual data.
postgresql will disable database access during the
migration and this will interfere with the running instance. There is
typically no rush to do the migration, so this is usually a task for a
scheduled maintenance window. Declare a time when all devices can be taken
offline and put a replacement site in place of the apache configuration to
prevent database access during the migration.
Determining the active cluster¶
The output of
pg_lsclusters includes the port number of each cluster.
To ensure that the correct cluster is upgraded, check the
/etc/lava-server/instance.conf for the current instance. If
multiple clusters are shown,
postgresql will upgrade to the latest version,
so ensure that any intermediate clusters are also stopped before starting the
Performing the migration¶
Debian gives a notice similar to this when a new version of postgres is installed:
Default clusters and upgrading ------------------------------ When installing a postgresql-X.Y package from scratch, a default cluster 'main' will automatically be created. This operation is equivalent to doing 'pg_createcluster X.Y main --start'. Due to this default cluster, an immediate attempt to upgrade an earlier 'main' cluster to a new version will fail and you need to remove the newer default cluster first. E. g., if you have postgresql-8.2 installed and want to upgrade to 8.3, you first install postgresql-8.3: apt install postgresql-8.3 Then drop the default 8.3 cluster: pg_dropcluster 8.3 main --stop And then upgrade the 8.2 cluster to 8.3: pg_upgradecluster 8.2 main
Upgrading a cluster combines
two copies of the database at one point). Ensure that you have enough
available space on the disc, especially with a large database. If
pg_upgradecluster is interrupted by the lack of disc space it will
not harm the system and full rollback will be applied automatically.
Check your existing clusters:
$ sudo pg_lsclusters
Stop postgresql (stops both versions):
$ sudo service postgresql stop
Drop the main cluster of the NEW postgres as this is empty:
$ sudo pg_dropcluster 9.4 main --stop
Postgresql knows which version is the current default, so just tell postgresql which is the old version to migrate the data into the (empty) new one:
$ sudo pg_upgradecluster 9.3 main Disabling connections to the old cluster during upgrade... Restarting old cluster with restricted connections... Creating new cluster 9.4/main ... config /etc/postgresql/9.4/main data /var/lib/postgresql/9.4/main locale en_GB.UTF-8 port 5433 Disabling connections to the new cluster during upgrade... Roles, databases, schemas, ACLs... Fixing hardcoded library paths for stored procedures... Upgrading database postgres... Analyzing database postgres... Fixing hardcoded library paths for stored procedures... Upgrading database lavaserver... Analyzing database lavaserver... Fixing hardcoded library paths for stored procedures... Upgrading database devel... Analyzing database devel... Fixing hardcoded library paths for stored procedures... Upgrading database template1... Analyzing database template1... Re-enabling connections to the old cluster... Re-enabling connections to the new cluster... Copying old configuration files... Copying old start.conf... Copying old pg_ctl.conf... Stopping target cluster... Stopping old cluster... Disabling automatic startup of old cluster... Configuring old cluster to use a different port (5433)... Starting target cluster on the original port... Success. Please check that the upgraded cluster works. If it does, you can remove the old cluster with pg_dropcluster 9.3 main
Check that the instance is still running. Note that the port of the new postgresql server will have been upgraded to the port used for the old postgresql server automatically. Check that this is the case:
$ grep port /etc/postgresql/9.4/main/postgresql.conf port = 5432
Drop the old cluster:
$ sudo pg_dropcluster 9.3 main
Now the old database package can be removed:
$ sudo apt remove postgresql-9.3
LAVA needs to control and output the list of dependencies in a variety
of formats. Building Docker images and running unit tests in an LXC
need an updated list of binary package names suitable for the
distribution and suite of the LXC. Each needs to cope with dependencies
outside the specified suite, e.g. stable releases which need backports.
Building the LAVA Debian packages themselves also requires a properly
up to date list of dependencies - including minimum versions. Each set
of dependencies needs to be specific to each LAVA binary package -
lava-server has different dependencies to
LAVA has several dependencies which are not available via PyPi or pip
requirements.txt file is therefore misleading. However, the
format of this file is still useful in building the LAVA packages.
Therefore, LAVA has the
./share/requires.py script which can be
used to output the preferred format, depending on the arguments. The
script is also included in the
lava-dev package as
The dependencies MUST be installed in the specified release of the specified distribution for LAVA to work, so take care before pushing a merge request to add package names to the support. Make sure your merge request includes a change to the relevant requirement YAML files for all supported distributions or the CI will fail.
Some distributions support
Recommends level dependencies. These are
typically intended to be installed by ~90% of installations but give
flexibility for other use cases.
Recommends are not handled by
requires.py at all. The packages must be listed explicitly by the
maintainer of the packaging for the distribution.
exists so that automated processes, like CI, can have a reliable but
minimal set of packages which must be installed for the specified
package to be installable. To use a minimal installation, each package
listed by ./share/requires.py` can be installed without its
recommended packages using the
apt install --no-install-recommends
requires.py does not currently support dependencies based on the
architecture of the installation. (Currently, only
includes architecture-sensitive packages.)
Outputting the requirements.txt format¶
Processes which need the version string can use the original output
format which mimics
$ ./share/requires.py --package lava-server --distribution debian --suite buster django>=1.10 PyYAML docutils>=0.6 jinja2 psycopg2 pytz pyzmq requests simplejson voluptuous>=0.8.8
Outputting a list of binary package names¶
This is intended to be passed directly to a package installer like
apt-get together with the other required commands and options.
The caller determines the
suite, so to use with buster-backports,
-t buster-backports option would also be added to the
apt-get commands before appending the list of packages.
(Line breaks are added for readability only):
$ ./share/requires.py --package lava-server --distribution debian --suite buster --names python3-django python3-yaml python3-docutils \ python3-jinja2 python3-psycopg2 python3-tz python3-zmq python3-requests \ python3-simplejson python3-voluptuous
Adding packages needed for the unittests¶
Some packages are only required to allow the unittests to pass. To add
these packages, use the
--unittest option, in combination with
--names. These packages need to be added to the installation as
well as the base list of packages using
$ ./share/requires.py --package lava-server --distribution debian --suite unstable --names --unittest python3-pytest-django python3-pytest python3-pytest-cov
$ ./share/requires.py --package lava-dispatcher --distribution debian --suite unstable --names --unittest pyocd-flashtool gdb-multiarch git schroot lxc img2simg simg2img u-boot-tools docker.io xnbd-server telnet qemu-system-x86 qemu-system-arm
or not packaged at all.
static/js directories and maintains a list of files which are replaced with
symlinks during a Debian package build. The list is in
the same script or provide patches if the paths within the script need
The primary concern is security fixes. Distributions release with a particular
release of LAVA and may need to fix security problems in that release. If the
file is replaced by a symlink to an external package in the distribution, then
the security problem and fix migrate to that package. LAVA tracks these files
different version to the one available in the distribution, need to be patched
code and patches to these files will take effect in LAVA after a simple restart
of apache and a clearing of any browser cache. Problems arise when the
.min.js file which is not suitable for editing or patching.
READMEin the relevant
js/directory along with details, if any, of how a modified file can be minified or whether a modified file should simply replace the minified file.
From time to time, there can be packaging changes required to handle changes in the LAVA upstream codebase. If you have write access to the packaging repository, changes to the packaging can be tested by pushing to your fork of lava.git and making a local commit. Then build as normal:
Building for other architectures¶
lava-server is the same for all architectures but
lava-dispatcher has a
different set of dependencies depending on the build architecture. To build an
arm64 package of lava-dispatcher using the developer scripts, use:
$ /usr/share/lava-server/debian-dev-build.sh -a arm64 -B
Debugging Django issues¶
When trying to investigate LAVA web pages generation we advise you to use django-debug-toolbar. This is a Django application that provide more information on how the page was rendered, including:
For instance, the toolbar is a really helpful resource to debug the Django ORM.
On a Debian system, just run:
$ apt-get install python-django-debug-toolbar
python-django-debug-toolbar package is installed, the toolbar
needs to be enabled in the instance. Two settings are required in
settings.conf is JSON syntax, so ensure that the previous
line ends with a comma and that the resulting file validates as JSON.
The toolbar can be disabled without disabling django debug but django must be in debug mode for the toolbar to be loaded at all.
django related services to complete the installation of the
sudo service lava-server-gunicorn restart sudo apache2ctl restart
Installation can be checked using
lava-server manage shell:
>>> from django.conf import settings >>> 'debug_toolbar' in settings.INSTALLED_APPS True
In order to see the toolbar, you should also check the value of INTERNAL_IPS. Local
::1 are enabled by default.
To add more addresses, set
INTERNAL_IPS to a list of addresses in
/etc/lava-server/settings.conf, (JSON syntax) for example:
"INTERNAL_IPS": ["192.168.0.5", "10.0.0.6"],
These value depends on your setup. But if you don’t see the toolbar that’s the first think to look at.
Apache then needs access to django-debug-toolbar CSS and JS files:
sudo su - cd /usr/share/lava-server/static/ ln -s /usr/lib/python3/dist-packages/debug_toolbar/static/debug_toolbar .
/etc/lava-server/settings.conf remove the reference to htdocs in
STATICFILES_DIRS. Django-debug-toolbar does check that all directories
STATICFILES_DIRS exists. While this is only a leftover from
previous versions of LAVA installer that is not needed anymore.
Once the changes are complete, ensure the settings are loaded by restarting both apache2 and django:
sudo service lava-server-gunicorn restart sudo apache2ctl restart
Keep in mind that django-debug-toolbar has some overhead on the web page generation and should only be used while debugging.
Django-debug-toolbar can be disabled, while not debugging, by changing the
false or by changing the
̀DEBUG level in
Ensure the settings are reloaded by restarting both apache2 and django:
sudo service lava-server-gunicorn restart sudo apache2ctl restart