Multiple GitLab Project CI Structure

When using GitLab’s repository mirroring functionality you will undoubtedly end up in a case where you will be required to manage vastly different pipelines depending on the instance. These examples are meant to provide guidance on some advised methods to handle such a case.

Note

Even with similar workflows, because it is unlikely that two instances uses the same runner tags, trying to support two instances quickly becomes impossible without the following tricks. (As of April 2021, Gitlab does not allow conditional tags runner1 OR runner2).

Single YAML File

It is possible to manage your pipelines for multiple GitLab instances through a single .gitlab-ci.yml file. This can be seen to great success implemented by the GAMESS team and their use of GitLab rules and examining the CI_SERVER_HOST predefined variable.

global-job:
  script:
    - make test

.rules-siteA
  rules:
  - if: '$CI_SERVER_HOST != "gitlab.siteA.example.com"'
    when: never

siteA-job:
  extends: .rules-siteA
  script:
    - make test-siteA

.rules-siteB
  rules:
  - if: '$CI_SERVER_HOST != "gitlab.siteB.example.com"'
    when: never

siteB-job:
  extends: .rules-siteB
  script:
    - make test-siteB

As you may imagine from reading the example any jobs with the rules defined will only run when CI is triggered from the associated server.

Note

We purposefully wrote the rule so that we exclude jobs (when: never) rather than include them. This is because, “Rules are evaluated in order until a match is found”.

Multiple YAML Files

Maintaining a series of rules to enforce behaviors on different servers may not be supportable. In this case it may be easier to manage completely separate pipeline files for each GitLab instance. This is achievable since the CI configuration file (default: .gitlab-ci.yml) is configurable on a per project basis. To do so simply navigate to Settings –> CI/CD –> General pipelines:

By defining a new Custom CI configuration path on each GitLab instance we can manage facility specific configurations. Looking at the contents of an example project:

.gitlab-ci.yml         # Configuration for GitLab.com.
siteA.gitlab-ci.yml    # Configuration for SiteA's GitLab instance.
siteB.gitlab-ci.yml    # Configuration for SiteB's GitLab instance.