How to fix Gitlab CI error during connect: Post http://docker:2375/v1.40/auth: dial tcp: lookup docker on … no such host. I spent more than 1 hour to fix it. And I am totally not sure that I will remember it 🙂

The source is here:

This error occurs with docker-based gitlab runners such as the one we’re that are configured using a docker executor. The error message means that the inner docker container doesn’t have a connection to the host docker daemon.

In order to fix this, set these options in [runners.docker] in your gitlab-runner config.toml:

The content of /etc/gitlab-runner/config.toml is: