Consider not rebuilding QA images since they're built in GitLab's pipelines already
In the GitLab pipelines, we already build the QA image (for the Merge Result): https://gitlab.com/gitlab-org/gitlab/-/blob/7bec95a990a0da44bc5c778ca78cf090b77f589b/.gitlab/ci/review.gitlab-ci.yml#L1-10
It looks like omnibus-gitlab
's pipelines rebuild a QA image (potentially for the non Merge Result commit, though, due to https://gitlab.com/gitlab-org/gitlab/-/blob/7bec95a990a0da44bc5c778ca78cf090b77f589b/scripts/trigger-build#L141) so this may duplicate the work for no good reason.
The fact that in GitLab's pipelines the image is build for the Merge Result and not in omnibus-gitlab
's pipelines is actually one good reason to use the image built in GitLab's pipeline since it would mean the image is "closer" to master
.
One thing to solve, though is that the image is tagged as ${CI_REGISTRY}/${CI_PROJECT_PATH}/gitlab-ee-qa:${CI_COMMIT_REF_SLUG}
(https://gitlab.com/gitlab-org/gitlab/-/blob/7bec95a990a0da44bc5c778ca78cf090b77f589b/.gitlab/ci/review.gitlab-ci.yml#L8), but the omnibus-gitlab
is tagged with the commit SHA (e.g. https://gitlab.com/gitlab-org/build/omnibus-gitlab-mirror/-/jobs/587107397), as well as the QA image (e.g. https://gitlab.com/gitlab-org/build/omnibus-gitlab-mirror/-/jobs/587107399), and the QA image in gitlab-qa-mirror
is inferred from it (e.g. https://gitlab.com/gitlab-org/gitlab-qa-mirror/-/jobs/587211159).