Login attempts to Nexus OSS Docker repo throwing 404 - docker

Question

We are trying to set up a Docker repository in Nexus OSS (v3.3.2-02) in a Kubernetes cluster, and having issues logging in to it. We are intending to have a proxy set up for DockerHub, a private repo, and a group repo to tie the two together, using the below configurations
Hosted
Proxy
Group
giving us the following list:
But when I try to log in to the repository, it appears it's trying to forward me to a /v2 endpoint, which is throwing a 404 error:
> docker login -u <user> -p <pass> https://repo.myhost.com:443
Error response from daemon: login attempt to https://repo.myhost.com:443/v2/ failed with status: 404 Not Found
I would like to add that we have Maven and NPM repositories set up in this same instance and they're working, so it appears Nexus itself is OK, but there's something wrong with the Docker configuration.
I don't know why this request is trying to send me to the /v2 endpoint when trying to log in. What am I missing?

Answer 1

Docker requires very specific URL layout and does not allow for any context URL hence the need for Docker connectors to allow Docker client to connect to NXRM. Your screenshot shows you have configured Docker connector for your Docker hosted repository on port 444, but your terminal capture shows you're attempting to connect on port 443 which isn't your Docker connector port. The error message you have suggest your NXRM server indeed runs on port 443, but because of how Docker works you need to access it using port 444. Please try: docker login -u <user> -p <pass> https://repo.myhost.com:444 so it attempts to use your Docker connector port. Also, it's always a good idea to run the latest version of Nexus.

Answer 2

In an experiment I just ran (docker-machine, virtualbox, macOS), when the server was 1.13.1 (as was the docker cli), it made a graceful degradation from /v2 down to /v1, like so:
level=debug msg="Calling GET /_ping"
level=debug msg="Calling GET /v1.26/version"
level=debug msg="Calling GET /_ping"
level=debug msg="Calling GET /v1.26/version"
level=debug msg="Calling GET /_ping"
level=debug msg="Calling GET /v1.26/info"
level=debug msg="Calling POST /v1.26/auth"
level=debug msg="attempting v2 login to registry endpoint https://192.168.2.103:9999/v2/"
level=info msg="Error logging in to v2 endpoint, trying next endpoint: Get https://192.168.2.103:9999/v2/: EOF"
level=debug msg="attempting v1 login to registry endpoint https://192.168.2.103:9999/v1/"
level=info msg="Error logging in to v1 endpoint, trying next endpoint: Get https://192.168.2.103:9999/v1/users/: dial tcp 192.168.2.103:9999: getsockopt: connection refused"
level=error msg="Handler for POST /v1.26/auth returned error: Get https://192.168.2.103:9999/v1/users/: dial tcp 192.168.2.103:9999: getsockopt: connection refused"
but after I upgraded the server to 17.06.0-ce (still with 1.13.1 cli), it only attempted /v2 and then quit:
level=debug msg="Calling GET /_ping"
level=debug msg="Calling GET /_ping"
level=debug msg="Calling GET /v1.30/version"
level=debug msg="Calling GET /_ping"
level=debug msg="Calling GET /v1.30/info"
level=debug msg="Calling POST /v1.30/auth"
level=debug msg="attempting v2 login to registry endpoint https://192.168.2.103:9999/v2/"
level=info msg="Error logging in to v2 endpoint, trying next endpoint: Get https://192.168.2.103:9999/v2/: tls: oversized record received with length 21584"
level=error msg="Handler for POST /v1.30/auth returned error: Get https://192.168.2.103:9999/v2/: tls: oversized record received with length 21584"
So the answer appears to be that one either needs to teach Nexus to respond correctly to the /v2 endpoints (as it really should be doing already), or downgrade the dockerd back down to a version that speaks the /v1 api if that is the behavior you're after

Answer 3

Not sure if this is going to help, but the browser based URL does not have port number in it, and could login with my credentials. Example browser based URL below.
https://nexus.mysite.net/
However I had to key in the following
docker login -u -p https://nexus.mysite.net/
I am greeted with the following
Error response from daemon: login attempt to https://nexus.mysite.net/v2/ failed with status: 404 Not Found
Giving the right port number did not show up the above error and I could login from the CLI as follows.
docker login -u the-user-name -p the-password https://nexus.mysite.net:7000
(in my case the correct port number was 7000).
Hope this helps.