Maybe I’m misunderstanding? For GitLab this should be doable by two different ways.
The first is merge trains, which merges requests one by one to prevent this exact outcome. You just have to force all deployments to be done via a merge request. That’s the downside.
The second being forcing a GitLab Runner to run one job at a time. Tag it as “deployer” then ensure all deployment jobs are marked as “deployer”. That runner will pick up deployment jobs one by one in order of first creation.
The first is merge trains, which merges requests one by one to prevent this exact outcome. You just have to force all deployments to be done via a merge request. That’s the downside.
The second being forcing a GitLab Runner to run one job at a time. Tag it as “deployer” then ensure all deployment jobs are marked as “deployer”. That runner will pick up deployment jobs one by one in order of first creation.