Docker Registry incorrectly claims an expired CA cert - ssl

Question

I followed the Docker Registry installation docs precisely, and have a registry running on a remote Ubuntu VM. On that VM, the Docker container is running with the following command:
docker run -d -p 5000:5000 --restart=always --name registry \
-v `pwd`/auth:/auth \
-e "REGISTRY_AUTH_HTPASSWD_REALM=Registry Realm" \
-e REGISTRY_AUTH_HTPASSWD_PATH=/auth/htpasswd \
-v `pwd`/certs:/certs \
-e REGISTRY_HTTP_TLS_CERTIFICATE=/certs/registry.crt \
-e REGISTRY_HTTP_TLS_KEY=/certs/registry.key \
registry:2
On the remote VM, I have the following directory structure:
/home/myuser/
certs/
registry.crt
registry.key
/etc/docker/certs.d/myregistry.example.com:5000/
ca.crt
ca.key
The ca.crt is the same exact cert as ~/certs/registry.crt (just renamed); same goes for ca.key and registry.key being the same/just renamed. I created the ca* files per a suggestion from the error output you'll see below.
I am almost 100% sure the CA cert is still valid, although any help ruling that out (e.g. how can I actually tell?) would be appreciated. When I start the container and look at the Docker logs, I don't see any errors.
I then attempt to login from my local laptop (Mac):
docker login myregistry.example.com:5000
It queries me for my username, password and email (although I don't recall ever specifying an email when setting up Basic Auth). After entering these correctly (I have checked and double checked...) I get the following error:
myuser#mymachine:~/tmp$docker login myregistry.example.com:5000
Username: my_ciuser
Password:
Email: myuser#example.com
Error response from daemon: invalid registry endpoint https://myregistry.example.com:5000/v0/:
unable to ping registry endpoint https://myregistry.example.com:5000/v0/ v2 ping attempt failed with error:
Get https://myregistry.example.com:5000/v2/: x509: certificate has expired or is not yet valid
v1 ping attempt failed with error: Get https://myregistry.example.com:5000/v1/_ping: x509:
certificate has expired or is not yet valid. If this private registry supports only HTTP or
HTTPS with an unknown CA certificate, please add
`--insecure-registry myregistry.example.com:5000` to the daemon's
arguments. In the case of HTTPS, if you have access to the registry's CA
certificate, no need for the flag; simply place the CA certificate
at /etc/docker/certs.d/myregistry.example.com:5000/ca.crt
So from my perspective, I guess the following are possible:
The CA cert is invalid (if so, why?!?)
The CA cert is an intermediary cert (if so, how can I tell?)
The CA cert is expired (if so, how do I tell?)
This is a bad error message, and some other facet of the registry is not configured properly (if so, how do I troubleshoot further?)
Perhaps my cert is not located in the correct place on the server, or doesn't have the right permissions set (if so, where does the cert need to be?)
Something else that I would never expect in a million years
Any ideas/thoughts?

Answer 1

As said in the error message:
... In the case of HTTPS, if you have access to the registry's CA
certificate, no need for the flag; simply place the CA certificate
at /etc/docker/certs.d/myregistry.example.com:5000/ca.crt
where myregistry.example.com:5000 - your CN with port.
You should copy your ca.crt into each Docker Daemon that will connect to your Docker Registry and put it in this folder: /etc/docker/certs.d/myregistry.example.com:5000/ca.crt
After this action you need to restart Docker daemon, for example, via sudo service docker stop && service docker start on CentOS (or call similar procedure on your OS).

Answer 2

I had the similar error:
Then I added my private registry to the insecureregistries list.
See below image for docker-desktop