“docker pull” certificate signed by unknown authority

Question

I was trying to pull a docker image from a docker registry but hit the following issue:

$ docker pull //          


        

Answer 1

You may need to restart the docker service to get it to detect the change in OS certificates.

Docker does have an additional location you can use to trust individual registry server CA. You can place the CA cert inside /etc/docker/certs.d//ca.crt. Include the port number if you specify that in the image tag, e.g in Linux.

/etc/docker/certs.d/my-registry.example.com:5000/ca.crt

or in Windows 10:

C:\ProgramData\docker\certs.d\ca.crt