Learn Docker - Fundamentals of Docker 19.x - Second Edition

Deploying a multi-service stack

In Chapter 11, Docker Compose, we used an application consisting of two services that were declaratively described in a Docker compose file. We can use this compose file as a template to create a stack file that allows us to deploy the same application into a Swarm. The content of our stack file, called pet-stack.yaml, looks like this:

version: "3.7"services: web:   image: fundamentalsofdocker/ch11-web:2.0   networks:   - pets-net   ports:   - 3000:3000   deploy:     replicas: 3 db:   image: fundamentalsofdocker/ch11-db:2.0   networks:   - pets-net   volumes:   - pets-data:/var/lib/postgresql/datavolumes: pets-data:networks: pets-net: driver: overlay

We request that the web service has three replicas, and both services are attached ...