7.2.1. Azure Pipelines - Container Agents.md

Container agents

• The agent will first fetch and start the container.
  • Then, each step of the job will run inside the container
    • or you can set agent on task level

Linux agents

• E.g.:

    pool:
      vmImage: 'ubuntu-16.04'
    container: ubuntu:16.04
    steps:
    - script: printenv

• On your agent host, ensure:

  • Docker is installed
  • Agent has permission to access the Docker daemon

• Container requirements:

  • Bash
  • glibc-based
  • Can run Node.js (which the agent provides)
  • Does not define an ENTRYPOINT
  • USER has access to groupadd and other privileges commands without sudo

Windows agents

• E.g.

    pool:
      vmImage: 'windows-2019'
    container: mcr.microsoft.com/windows/servercore:ltsc2019
    steps:
    - script: set

Service containers

• Spin up multiple containers
• Automatically create, network, and manage the lifecycle
• Read more: Microsoft documentation

Service container example

  resources:
    containers:
    - container: my_container
      image: ubuntu:16.04
    - container: nginx
      image: nginx
    - container: redis
      image: redis

  pool:
    vmImage: 'ubuntu-16.04'

  container: my_container

  services:
    nginx: nginx
    redis: redis

  steps:
  - script: |
      apt install -y curl
      curl nginx
      apt install redis-tools
      redis-cli -h redis ping

• Fetches the latest nginx and redis containers from Docker Hub and then starts the containers
• The containers are networked together so that they can reach each other by their services name.
• Pipeline then runs the apt, curl and redis-cli commands inside the ubuntu:16.04 container.
• From inside this job container, the nginx and redis host names resolve to the correct services using Docker networking
• All containers on the network automatically expose all ports to each other