Proxy cache

[michmike]

enable proxy cache for Harbor.

This is very useful in situations of intermittent network connectivity where you still need access to local images. the expectation is that the network will go off in ROBO or IoT scenarios

Of course, the standard use case of reducing redundant image pulls across the network applies here

[xaleeks]

@michmike Is this referring to deploying a worker instance close to the edge nodes functioning specifically as a local registry mirror for a central Harbor and have the edge daemons pointing to it for local pulls? or is Harbor being used as proxy cache to pull from other registries like Docker hub and such? I mean is this this linking Harbor instances or w/ rest of the registry ecosystem.

somethings to think about

• once pulled, how does long is it kept in cache for other clients before cleaned, there should be some LRU (least recently used) algorithm for determination
• 'subsequent' pulls of any particular image can be based on just the image manifest
• user pulling image needs to be properly authenticated and authorization checked before redirected to the local cache
• will this be able to work w/ rbac
• when to use this vs deploying another harbor cluster and relying on regular replication

[salcinad]

@michmike
are you referring to the: https://github.com/goharbor/harbor/blob/master/contrib/Configure_mirror.md

our need is that we don't pull Images from "registry-1.docker.io" (from Docker hub in Internet) but from internal Harbor Register which will act as Proxy/Cache ( for example this Option is available in Nexus 3), which will Cache and if not cached pull Images from Docker hub and provide to user.

[michmike]

proxy cache is a feature of registry v2. this is what i meant - https://mtijhof.wordpress.com/2018/07/23/using-nexus-oss-as-a-proxy-cache-for-docker-images/

[michmike]

we of course don't have to restrict the Harbor capabilities, so it could pull images as a cache from any type of replication target we can support

[stonezdj]

proxy cache is a feature of registry v2. this is what i meant - https://mtijhof.wordpress.com/2018/07/23/using-nexus-oss-as-a-proxy-cache-for-docker-images/

The pull through proxy only works for docker hub, it doesn't work for other registry repository.

[xaleeks]

@stonezdj yes it seems the docker registry's own proxy mechanism still only works for docker hub. There's a pr on supporting other self hosted registries but still unmerged after 2 years
moby/moby#34319