[JIRA] (OVIRT-2591) Add a distributed docker-cache

Add a distributed docker-cache ------------------------------ Key: OVIRT-2591 URL: https://ovirt-jira.atlassian.net/browse/OVIRT-2591 Project: oVirt - virtualization made easy Issue Type: Improvement Reporter: Roman Mohr Assignee: infra Priority: High What? If CI builds get heavy and things are running inside containers, I expect that the CI system proactively tries to optimize when it can. Since the CI system provides the docker installation, I would expect that under some conditions, it automatically puts heavy docker builds in a distributed cache in the cluster. Examples on how this can achieved are listed in [1] and [2]. Why? Dockerfiles have the advantage that we can isolate our biuld-steps in a Dockerfile. This gives reproducibility, but also means that e.g. curl downloads or RPM installs are not visible for the CI system. Therefore it is beneficial for the CI system and the user (more speed and less utilization), to put docker images with their build chain into a distributed cache and pre-fetch the cache into the docker cache of the build slot. Pre-fetching based on e.g. gibhub project probably makes sense. [1] https://runnable.com/blog/distributing-docker-cache-across-hosts [2] https://blog.codeship.com/building-a-remote-caching-system/