I have been doing Clair Scans for the past month using DinD without any issue, today I migrated to runner 12.2 and Gitlab EE 12.2.4 and the Docker service never seems available, after some tries like 4 or 5 retries it can connect, but this is a new behavior that I did not have before. The DinD seems to come up, but then it is not available.
Sorry to hear you’re having issues with GitLab Runner and DinD after upgrading.
It sounds like you may be hitting this issue:
Can you please try the hotfix outlined here and let us know if it fixes the issue?
Actually I had that issue, then solved it, but this is a new one, started just yesterday. The problem is that even though the Service appears to be running i cannot connect to it from the runner. I will follow up on that issue and also create a support ticket with more details since we are using the EE version.