Docker Stacks

Docker Stack sits at a higher level than Docker containers and helps to manage the orchestration of multiple containers across several machines. Docker Stack is run across a Docker Swarm.

Docker Stack can be seen as the Docker Swarm version of Docker Compose.

For example, in Docker Stack, we also have compose-like files that essentially do a very similar thing: build Docker services from images.

Putting everything together that we've learned, here is a file called stack.yml defining a Docker stack:

version: '3.3'
services:
  router:
    image: traefik:v2.2
    deploy:
      placement:
        constraints:
          - node.role == manager
    volumes:
      - "/var/run/docker.sock:/var/run/docker.sock:ro"
    networks:
      - maestro-production

networks:
  maestro-production:
    external: true

We can now deploy this stack using the command:

docker stack deploy -c stack.yml stack_name --with-registry-auth

The --with-registry-auth flag allows the stack to download images from private DockerHub repositories, assuming your docker login credentials entered have access to it.

Here is an example diagram that explains how everything we've learned in Docker comes together: