[diftraku]

One point worth of note when it comes to Docker caching, more specifically pulling images, is the rate-limiting on Docker Hub.

While hosted GitLab might make use of a transparent pull-through cache (as I've gathered from glancing at relevant parts of the docs), you can benefit a lot by using one with your own local GitLab instance (assuming it does not already provide it via container registry).

We ended up switching to Harbor[1] from the vanilla registry and almost by chance stumbled on the fact that it supported a pull-through cache from various other sources (including Docker Hub).

This was especially useful after we hit the rate-limit after one of our pipelines got out of hand and decided to rebuild every locally hosted Docker image (both internal and external).

[1]: https://goharbor.io/