Docker Compose in 5 Minutes

· Docker Compose is a “tool for defining and running your multi-container Docker applications”.

· Just need to download Docker Compose binary.

· Docker Compose is based on a docker-compose.yml file. This file defines all of the containers and settings you need to launch.

· Docker Compose supports all of the properties which can be defined using docker run.

Docker Compose to manage the orchestration of multi-container applications.

When working with multiple containers, it can be difficult to manage the starting along with the configuration of variables and links. To solve this problem, Docker has a tool called Docker Compose to manage the orchestration, of launching, of containers.

Docker Compose is based on a docker-compose.yml file. This file defines all of the containers and settings you need to launch

Docker Compose supports all of the properties which can be defined using docker run.

Installation of Docker Compose

$ sudo yum install -y docker

$ service docker start

$ sudo curl -L https://github.com/docker/compose/releases/download/1.24.1/docker-compose-`uname -s`-`uname -m` -o /usr/local/bin/docker-compose

$ sudo chmod +x /usr/local/bin/docker-compose

$ ln -s /usr/local/bin/docker-compose /usr/bin/docker-compose

$ docker-compose –version

Simple three steps to use Docker Compose.

1. Define your app’s environment with a Dockerfile so it can be reproduced anywhere.

2. Define the services that make up your app in docker-compose.yml so they can be run together in an isolated environment.

3. Lastly, run docker-compose up and Compose will start and run your entire app.

Lab Practice:

Create Dockerfile and docker-compose.yaml

vi Dockerfile

FROM alpine

Maintaner Prakash

EXPOSE 4000

vi docker-compose-yaml

web:

build: .

links:

- redis

ports:

- “4000”

- “8000”

redis:

image: redis:alpine

volumes:

- /var/redis/data:/data

With the created docker-compose.yml file in place, you can launch all the applications with a single command of up. If you wanted to bring up a single container, then you can use up <name>.

$ docker-compose up -d

$ docker-compose ps

$ docker-compose logs

Docker Scale

$ docker-compose scale web=2

$ docker-compose ps

Name Command State Ports

tutorial_redis_1 docker-entrypoint.sh redis … Up 6379/tcp

tutorial_web_1 npm start Up 0.0.0.0:32700->4000/tcp, 0.0.0.0:32700->8000/tcp

tutorial_web_2 npm start Up 0.0.0.0:32701->4000/tcp, 0.0.0.0:32701->8000/tcp

$ docker-compose down

to stop a set of containers you can use the command docker-compose stop

To remove all the containers use the command docker-compose rm