1 files changed, 127 insertions, 0 deletions
diff --git a/docs/devel/ci.rst b/docs/devel/ci.rst
new file mode 100644
index 0000000000..b3bf3ef615
--- /dev/null
+++ b/docs/devel/ci.rst
@@ -0,0 +1,127 @@
+==
+CI
+==
+
+QEMU has configurations enabled for a number of different CI services.
+The most up to date information about them and their status can be
+found at::
+
+   https://wiki.qemu.org/Testing/CI
+
+Jobs on Custom Runners
+======================
+
+Besides the jobs run under the various CI systems listed before, there
+are a number additional jobs that will run before an actual merge.
+These use the same GitLab CI's service/framework already used for all
+other GitLab based CI jobs, but rely on additional systems, not the
+ones provided by GitLab as "shared runners".
+
+The architecture of GitLab's CI service allows different machines to
+be set up with GitLab's "agent", called gitlab-runner, which will take
+care of running jobs created by events such as a push to a branch.
+Here, the combination of a machine, properly configured with GitLab's
+gitlab-runner, is called a "custom runner".
+
+The GitLab CI jobs definition for the custom runners are located under::
+
+  .gitlab-ci.d/custom-runners.yml
+
+Custom runners entail custom machines.  To see a list of the machines
+currently deployed in the QEMU GitLab CI and their maintainers, please
+refer to the QEMU `wiki <https://wiki.qemu.org/AdminContacts>`__.
+
+Machine Setup Howto
+-------------------
+
+For all Linux based systems, the setup can be mostly automated by the
+execution of two Ansible playbooks.  Create an ``inventory`` file
+under ``scripts/ci/setup``, such as this::
+
+  fully.qualified.domain
+  other.machine.hostname
+
+You may need to set some variables in the inventory file itself.  One
+very common need is to tell Ansible to use a Python 3 interpreter on
+those hosts.  This would look like::
+
+  fully.qualified.domain ansible_python_interpreter=/usr/bin/python3
+  other.machine.hostname ansible_python_interpreter=/usr/bin/python3
+
+Build environment
+~~~~~~~~~~~~~~~~~
+
+The ``scripts/ci/setup/build-environment.yml`` Ansible playbook will
+set up machines with the environment needed to perform builds and run
+QEMU tests.  This playbook consists on the installation of various
+required packages (and a general package update while at it).  It
+currently covers a number of different Linux distributions, but it can
+be expanded to cover other systems.
+
+The minimum required version of Ansible successfully tested in this
+playbook is 2.8.0 (a version check is embedded within the playbook
+itself).  To run the playbook, execute::
+
+  cd scripts/ci/setup
+  ansible-playbook -i inventory build-environment.yml
+
+Please note that most of the tasks in the playbook require superuser
+privileges, such as those from the ``root`` account or those obtained
+by ``sudo``.  If necessary, please refer to ``ansible-playbook``
+options such as ``--become``, ``--become-method``, ``--become-user``
+and ``--ask-become-pass``.
+
+gitlab-runner setup and registration
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The gitlab-runner agent needs to be installed on each machine that
+will run jobs.  The association between a machine and a GitLab project
+happens with a registration token.  To find the registration token for
+your repository/project, navigate on GitLab's web UI to:
+
+ * Settings (the gears-like icon at the bottom of the left hand side
+   vertical toolbar), then
+ * CI/CD, then
+ * Runners, and click on the "Expand" button, then
+ * Under "Set up a specific Runner manually", look for the value under
+   "And this registration token:"
+
+Copy the ``scripts/ci/setup/vars.yml.template`` file to
+``scripts/ci/setup/vars.yml``.  Then, set the
+``gitlab_runner_registration_token`` variable to the value obtained
+earlier.
+
+To run the playbook, execute::
+
+  cd scripts/ci/setup
+  ansible-playbook -i inventory gitlab-runner.yml
+
+Following the registration, it's necessary to configure the runner tags,
+and optionally other configurations on the GitLab UI.  Navigate to:
+
+ * Settings (the gears like icon), then
+ * CI/CD, then
+ * Runners, and click on the "Expand" button, then
+ * "Runners activated for this project", then
+ * Click on the "Edit" icon (next to the "Lock" Icon)
+
+Tags are very important as they are used to route specific jobs to
+specific types of runners, so it's a good idea to double check that
+the automatically created tags are consistent with the OS and
+architecture.  For instance, an Ubuntu 20.04 aarch64 system should
+have tags set as::
+
+  ubuntu_20.04,aarch64
+
+Because the job definition at ``.gitlab-ci.d/custom-runners.yml``
+would contain::
+
+  ubuntu-20.04-aarch64-all:
+   tags:
+   - ubuntu_20.04
+   - aarch64
+
+It's also recommended to:
+
+ * increase the "Maximum job timeout" to something like ``2h``
+ * give it a better Description