Use a TLS certificate - Docker

Question

I have already created a TLS certificate. Now I would like to tell my docker, how to use it. How do I do that?

Answer 1

You do this by creating a drop in systemd unit to modify the existing Docker systemd unit.

Create the file custom.conf in /etc/systemd/system/docker.service.d/:

If you want to restrict local users from using the docker unix socket remove the second -H command line option, if you already have a custom drop in unit you can add the -H and –tls* arguments to it.

[Service]
Environment="DOCKER_OPTS=-H=0.0.0.0:2376 -H unix:///var/run/docker.sock --tlsverify --tlscacert=/etc/docker/ssl/ca.pem --tlscert=/etc/docker/ssl/cert.pem --tlskey=/etc/docker/ssl/key.pem"

Reload systemd and the Docker service:

$ sudo systemctl daemon-reload
$ sudo systemctl restart docker