[JIRA] (OVIRT-2590) Cache Docker images in the datacenter

Cache Docker images in the datacenter ------------------------------------- Key: OVIRT-2590 URL: https://ovirt-jira.atlassian.net/browse/OVIRT-2590 Project: oVirt - virtualization made easy Issue Type: Improvement Reporter: Roman Mohr Assignee: infra What? As a user, I expect that I don't have to care about caching to speed up builds for the good of the CI system itself. Right now there exists a whitelist for docker images, which will not be remove from the build slot after the build. Instead of that I expect a clean build environment and that in general all images which I regularly use are cached in the cluster via e.g. a pull-through-cache [1]. Why? 1) Caching in a build slot is not very effective. CI runs do really-a-lot of almost identical things in a small time-window (e.g. days). If caching happens in the build-slot and many slots are present, then the cache utilization will be very low. 2) Whitelisting docker images extra for a slot where the registry runs in, is very error prone and since it is not cached across the cluster it is also very intransparent what the clear benefit for the user is. Especially when thinking about scaling a CI system, that seems to leak internal optimizations to the user. Fast builds are twice as important for the CI system than they are for the users (by default faster and lower utilization is always better than asking people to optimize on their side). [1] https://docs.docker.com/registry/recipes/mirror/