Gitlab-runner Docker container not binding on IPv4 socket


Please be gentle, complete beginner here!

Our university is running a self-hosted gitlab installation centrally, and a developer at my local institute is trying to set up gitlab-runner and connect it with that server.

We are running a fresh and default Ubuntu 20.04 LTS with Docker on it and have pulled and started the gitlab-runner container successfully, like this:

docker run -d --name gitlab-runner -p 8093:8093 --restart always -v /srv/gitlab-runner/config:/etc/gitlab-runner -v /var/run/docker.sock:/var/run/docker.sock gitlab/gitlab-runner:latest

However, it only binds to an IPv6 socket on port 8093, so [::]:8093, but not to IPv4. Our entire infrastructure is IPv4 though, so to reach it over the network, we’d need it to listen to e.g.

Some people on the web have suggested changing some sysctls globally, but they seem to be set correctly by default already, like:

net.ipv6.bindv6only = 0
net.ipv4.ip_forward = 1

What should we do to make the container listen on an IPv4 socket?

Thank you!