service/ci.md

@@ -34,6 +34,11 @@ the shared runners in a project?
 
 <!-- more in-depth procedure that may require interpretation -->
 
+## Building docker images
+
+TODO: document how to build docker images from GitLab CI. Maybe with
+podman or buildah? see below.
+
 ## Image security
 
 TODO: document how to create and use more secure Docker images. For
@@ -83,8 +88,11 @@ cluster, using this command:
           ci-runner-01.torproject.org
 
 The `profile::gitlab_runner` Puppet class deploys the GitLab runner
-code and hooks it into GitLab. But before enabling it on the instance,
-the following operations need to be performed:
+code and hooks it into GitLab. It uses the
+[gitlab_ci_runner](https://forge.puppet.com/modules/puppet/gitlab_ci_runner)
+module from Voxpupuli to avoid reinventing the wheel. But before
+enabling it on the instance, the following operations need to be
+performed:
 
  1. The shared runner token needs to be setup in Trocla, using: