I struggled getting a #Testcontainers container to talk back to a (mock) server in a #gitlab CI job. I finally got it working, and wrote down the solution (using `hostname -i`) in this post: www.aryweb.nl/2025/09/02/r...
aryweb.nl
Let Sibling Containers in GitLab CI talk back
When using GitLab CI with docker:dind, your job runs in a container and any containers you start (e.g. with Testcontainers) become sibling containers. If a sibling container needs to reach a server ru...