We are trying to setup 2 globally separate docker repositories in nexus. each with a group and several host repositories, and a proxy in each group pointing to the other server.
The goal is to allow docker-push into either instance, and then pull through cache if required on the other instance.
so instance 1 has
– dev (hosted)
– dev-instance2 (proxy to instance2/dev)
and instance 2 has
– dev (hosted)
– dev-instance1 (proxy to instance1/dev)
What we are finding is when a request for a image:tag that exists on the local instance comes in, it is not asking the remote instance if it has a newer sha of that image:tag combination, just returns the value from its hosted repository.
I have confirmed in access logs that no requests makes it to the remote instance. if i change it to a tag that does not exist in the local cache i get a request in the access logs from the local cache on the remote cache, but only when the image does not exist.
I have confirmed the exact same behaviour works on maven hosted repositories setup the same way.
On the local cache, the Remote repository is setup:
Negative cache disabled (unchecked)
metadata/component age set to -1
The group order is set to:
And if we change the order so that the remote is first, it works (but this would break the case where local is newer).
I have tried invalidating cache, and confirmed the remote repository is healthy (changing labels gets a request, changing order in group gets a positive hit)