What are 'services' in GitLab CI/CD and how do you use them?

Services are Docker containers that run alongside the main job container, providing supporting infrastructure like databases, message brokers, or a Docker daemon. They share a network namespace with the job container.

# Run tests with a PostgreSQL database service:
test-with-db:
  stage: test
  image: python:3.12
  services:
    - postgres:16-alpine          # starts a Postgres container
  variables:
    POSTGRES_DB: testdb
    POSTGRES_USER: postgres
    POSTGRES_PASSWORD: secret
    DATABASE_URL: "postgresql://postgres:secret@postgres/testdb"
  script:
    - pip install -r requirements.txt
    - python -m pytest

# Multiple services:
integration-test:
  image: node:20
  services:
    - redis:7-alpine
    - postgres:16-alpine
    - name: rabbitmq:3-management
      alias: rabbit             # access as "rabbit" hostname
  script:
    - npm test

# Service with alias and entrypoint override:
custom-service:
  services:
    - name: my-registry/my-service:latest
      alias: api-mock
      entrypoint: ["/usr/bin/api-mock"]
      command: ["--port", "8080"]

Services are accessible from the main job container using the service's image name (or alias) as the hostname. For example, a postgres:16 service is reached at hostname postgres. Set an alias when you need a custom hostname.

Invest now in Acorns!!! 🚀
Join Acorns and get your $5 bonus!

Acorns is a micro-investing app that automatically invests your "spare change" from daily purchases into diversified, expert-built portfolios of ETFs. It is designed for beginners, allowing you to start investing with as little as $5. The service automates saving and investing. Disclosure: I may receive a referral bonus.

Invest now!!! Get Free equity stock (US, UK only)!

Use Robinhood app to invest in stocks. It is safe and secure. Use the Referral link to claim your free stock when you sign up!.

The Robinhood app makes it easy to trade stocks, crypto and more.

Webull! Receive free stock by signing up using the link: Webull signup.