Docker Tutorial For Beginners : Part 4 (docker compose)

Abhishek Ghosh

By Abhishek Ghosh July 19, 2017 2:36 pm Updated on July 19, 2017

Docker Tutorial For Beginners : Part 4 (docker compose)

We have previous three guides, one is how to install Docker and run it , second one is on some management GUI and Docker Part 3. docker-compose.yml file is a YAML file that defines how the Docker containers will in production. In Part 4 of Docker Tutorial For Beginners, we will talk about Docker Compose, which peoples say containers in production, docker-compose etc.

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Docker Tutorial For Beginners : docker compose

So, already you are running at least one Docker example application which we have shown in first guide, you can push and pull from Docker registry. Now create a file in that application directory :

nano docker-compose.yml

1	nano docker-compose.yml

This will be prototype content of the file, replace the username/repo:tag with real data and image details :

version: "3"
services:
  web:
    image: username/repository:tag
    deploy:
      replicas: 7
      resources:
        limits:
          cpus: "0.1"
          memory: 64M
      restart_policy:
        condition: on-failure
    ports:
      - "80:80"
    networks:
      - webnet
networks:
  webnet:

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version: "3"

services:

web:

image: username/repository:tag

deploy:

replicas: 7

resources:

limits:

cpus: "0.1"

memory: 64M

restart_policy:

condition: on-failure

ports:

- "80:80"

networks:

- webnet

networks:

webnet:

Save the file. The above docker-compose.yml file tells Docker to pull the image where you uploaded in step 1 guide of this series, run 7 instances of the image as a service named web, limiting 10% of CPU and 64MB of RAM, restart containers if one fails, map port 80 on the host to web’s port 80, webnet is load-balanced network.

Run the load balanced app, application-name is your application :

docker swarm init
docker stack deploy -c docker-compose.yml application-name
docker stack ps application-name
docker stack deploy -c docker-compose.yml application-name

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docker swarm init

docker stack deploy -c docker-compose.yml application-name

docker stack ps application-name

docker stack deploy -c docker-compose.yml application-name

Docker compose has huge documentation on official website :

https://docs.docker.com/compose/overview/#automated-testing-environments

1	https://docs.docker.com/compose/overview/#automated-testing-environments

You’ll notice that there are hyperlinks to Get started with Django, Get started with Rails, Get started with WordPress, Frequently asked questions, Command line reference and Compose file reference.

We actually talked about WordPress before, again :

https://docs.docker.com/samples/wordpress/

1	https://docs.docker.com/samples/wordpress/

That is the Docker official image for WordPress. Please read the Docker’s official webpage for the full readme on how to use that Docker image and for information regarding contributing and issues. Then practice it.

Tagged With docker yml file tutorial beginners , networks yml docker webnet

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