docs/devel/ci-runners.rst.inc

   1 Jobs on Custom Runners
   2 ======================
   3
   4 Besides the jobs run under the various CI systems listed before, there
   5 are a number additional jobs that will run before an actual merge.
   6 These use the same GitLab CI's service/framework already used for all
   7 other GitLab based CI jobs, but rely on additional systems, not the
   8 ones provided by GitLab as "shared runners".
   9
  10 The architecture of GitLab's CI service allows different machines to
  11 be set up with GitLab's "agent", called gitlab-runner, which will take
  12 care of running jobs created by events such as a push to a branch.
  13 Here, the combination of a machine, properly configured with GitLab's
  14 gitlab-runner, is called a "custom runner".
  15
  16 The GitLab CI jobs definition for the custom runners are located under::
  17
  18   .gitlab-ci.d/custom-runners.yml
  19
  20 Custom runners entail custom machines.  To see a list of the machines
  21 currently deployed in the QEMU GitLab CI and their maintainers, please
  22 refer to the QEMU `wiki <https://wiki.qemu.org/AdminContacts>`__.
  23
  24 Machine Setup Howto
  25 -------------------
  26
  27 For all Linux based systems, the setup can be mostly automated by the
  28 execution of two Ansible playbooks.  Create an ``inventory`` file
  29 under ``scripts/ci/setup``, such as this::
  30
  31   fully.qualified.domain
  32   other.machine.hostname
  33
  34 You may need to set some variables in the inventory file itself.  One
  35 very common need is to tell Ansible to use a Python 3 interpreter on
  36 those hosts.  This would look like::
  37
  38   fully.qualified.domain ansible_python_interpreter=/usr/bin/python3
  39   other.machine.hostname ansible_python_interpreter=/usr/bin/python3
  40
  41 Build environment
  42 ~~~~~~~~~~~~~~~~~
  43
  44 The ``scripts/ci/setup/build-environment.yml`` Ansible playbook will
  45 set up machines with the environment needed to perform builds and run
  46 QEMU tests.  This playbook consists on the installation of various
  47 required packages (and a general package update while at it).  It
  48 currently covers a number of different Linux distributions, but it can
  49 be expanded to cover other systems.
  50
  51 The minimum required version of Ansible successfully tested in this
  52 playbook is 2.8.0 (a version check is embedded within the playbook
  53 itself).  To run the playbook, execute::
  54
  55   cd scripts/ci/setup
  56   ansible-playbook -i inventory build-environment.yml
  57
  58 Please note that most of the tasks in the playbook require superuser
  59 privileges, such as those from the ``root`` account or those obtained
  60 by ``sudo``.  If necessary, please refer to ``ansible-playbook``
  61 options such as ``--become``, ``--become-method``, ``--become-user``
  62 and ``--ask-become-pass``.
  63
  64 gitlab-runner setup and registration
  65 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  66
  67 The gitlab-runner agent needs to be installed on each machine that
  68 will run jobs.  The association between a machine and a GitLab project
  69 happens with a registration token.  To find the registration token for
  70 your repository/project, navigate on GitLab's web UI to:
  71
  72  * Settings (the gears-like icon at the bottom of the left hand side
  73    vertical toolbar), then
  74  * CI/CD, then
  75  * Runners, and click on the "Expand" button, then
  76  * Under "Set up a specific Runner manually", look for the value under
  77    "And this registration token:"
  78
  79 Copy the ``scripts/ci/setup/vars.yml.template`` file to
  80 ``scripts/ci/setup/vars.yml``.  Then, set the
  81 ``gitlab_runner_registration_token`` variable to the value obtained
  82 earlier.
  83
  84 To run the playbook, execute::
  85
  86   cd scripts/ci/setup
  87   ansible-playbook -i inventory gitlab-runner.yml
  88
  89 Following the registration, it's necessary to configure the runner tags,
  90 and optionally other configurations on the GitLab UI.  Navigate to:
  91
  92  * Settings (the gears like icon), then
  93  * CI/CD, then
  94  * Runners, and click on the "Expand" button, then
  95  * "Runners activated for this project", then
  96  * Click on the "Edit" icon (next to the "Lock" Icon)
  97
  98 Tags are very important as they are used to route specific jobs to
  99 specific types of runners, so it's a good idea to double check that
 100 the automatically created tags are consistent with the OS and
 101 architecture.  For instance, an Ubuntu 20.04 aarch64 system should
 102 have tags set as::
 103
 104   ubuntu_20.04,aarch64
 105
 106 Because the job definition at ``.gitlab-ci.d/custom-runners.yml``
 107 would contain::
 108
 109   ubuntu-20.04-aarch64-all:
 110    tags:
 111    - ubuntu_20.04
 112    - aarch64
 113
 114 It's also recommended to:
 115
 116  * increase the "Maximum job timeout" to something like ``2h``
 117  * give it a better Description