GitLab CI

Example using Docker socket

This applies if you have your own GitlabCI runner installed, use the Docker executor and you have /var/run/docker.sock mounted in the runner configuration.

See below for an example runner configuration:

[[runners]]
  name = "MACHINE_NAME"
  url = "https://gitlab.com/"
  token = "GENERATED_GITLAB_RUNNER_TOKEN"
  executor = "docker"
  [runners.docker]
    tls_verify = false
    image = "docker:latest"
    privileged = false
    disable_entrypoint_overwrite = false
    oom_kill_disable = false
    disable_cache = false
    volumes = ["/var/run/docker.sock:/var/run/docker.sock", "/cache"]
    shm_size = 0

Please also include the following in your GitlabCI pipeline definitions (.gitlab-ci.yml) that use Testcontainers:

variables:
  TESTCONTAINERS_HOST_OVERRIDE: "host.docker.internal"

The environment variable TESTCONTAINERS_HOST_OVERRIDE needs to be configured, otherwise, a wrong IP address would be used to resolve the Docker host, which will likely lead to failing tests.

Example using DinD (Docker-in-Docker)

In order to use Testcontainers in a Gitlab CI pipeline, you need to run the job as a Docker container (see Patterns for running inside Docker). So edit your .gitlab-ci.yml to include the Docker-In-Docker service (docker:dind) and set the DOCKER_HOST variable to tcp://docker:2375 and DOCKER_TLS_CERTDIR to empty string.

Caveat: Current docker releases (verified for 20.10.9) intentionally delay the startup, if the docker api is bound to a network address but not TLS protected. To avoid this delay, the docker process needs to be started with the argument --tls=false. Otherwise jobs which access the docker api at the very beginning might fail.

Here is a sample .gitlab-ci.yml that executes test with gradle:

# DinD service is required for Testcontainers
services:
  - name: docker:dind
    # explicitly disable tls to avoid docker startup interruption
    command: ["--tls=false"]

variables:
  # Instruct Testcontainers to use the daemon of DinD, use port 2375 for non-tls connections.
  DOCKER_HOST: "tcp://docker:2375"
  # Instruct Docker not to start over TLS.
  DOCKER_TLS_CERTDIR: ""
  # Improve performance with overlayfs.
  DOCKER_DRIVER: overlay2

test:
 image: gradle:5.0
 stage: test
 script: ./gradlew test