Docker IPTables Problem Running Registry

If you get IPTables related errors running the docker registry, consult this:

I just had the same issue on CentOS 7. I figured out that docker service is configured that way (/lib/systemd/system/docker.service):

After=network.target docker.socket Requires=docker.socket

It means, that docker service starts right after network.target started, and doesn't wait for network.target finished (including firewalld.service). Therefore firewalld.service actually started in parallel or after docker.service rewriting its nat rules. Changing docker.service settings to these solved the problem (/lib/systemd/system/docker.service):

After=network.target docker.socket Requires=network.target docker.socket

from https://github.com/sameersbn/docker-gitlab/issues/499