Gitlab-runner Docker container not binding on IPv4 socket

Hello,

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. 0.0.0.0:8093.

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!