Docker Compose

 Docker Compose

Docker Compose is another best tool for docker to set up multi-container environments. Using this creates a single compose file defining all the containers with their environments. You can easily use a single command to build images and run all the containers.

There is a three-step process to work with Docker Compose.

1. Define the application environment with Dockerfile for all services.
2. Create a docker-compose.yml file defining all services under the application.
3. Run docker-compose up to run all services under applications.

You must have Docker Engine installed on your system. If you don’t have already installed it, Visit our Docker installation section of this tutorial.

Install Docker Compose

Visit the Docker compose official Github page and download the latest version of the Docker compose tool. You can also install Docker compose 1.16.1 using the following command. Before installing the specific version, You must check the compatibility on the releases page with your docker version.

$ curl -L https://github.com/docker/compose/releases/download/1.16.1/docker-compose-uname -s-uname -m > /usr/local/bin/docker-compose
$ chmod +x /usr/local/bin/docker-compose

Docker Compose Example File

A docker-compose.yml file is required to create to start working with the docker compose. Below is a sample configuration file of version 3. This file has only one service added to it named web.

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version: '3' services:   db:      image: mysql      container_name: mysql_db      restart: always      environment:         - MYSQL_ROOT_PASSWORD="secret"   web:     image: apache     build: .     container_name: apache_web     restart: always     ports:       - "8080:80"

Docker Compose CLI Reference

The docker-compose command provides a number of subcommands to manage Docker containers with docker-compose. Please find below details of the subcommands. Before reading the below commands remember that you passed service name as an argument (not container name)

build –

The build option is used to build images for services for which build is defined.

$ docker-compose build             ## Build all services
$ docker-compose build web         ## Build single service

up –

Use to create docker containers with available services in docker-compose.yml file in the current directory. Use -d switch to launch containers in daemon mode.

$ docker-compose up -d            ## Create all containers
$ docker-compose up -d web        ## Create single container

down –

This will stop and delete all containers, network, and associated images for the services defined in a config file

$ docker-compose down           ## Restart all containers
$ docker-compose down web       ## Restart single container

ps –

This will list all containers created for the services defined in a config file with their status, port bindings, and command.

$ docker-compose ps 

exec –

This will execute a command to the running container. For example list files in containers associated with web service.

$ docker-compose exec web ls -l

start –

This will start stopped containers of the services defined in config file

$ docker-compose start            ## Start all containers
$ docker-compose start web        ## Start single container

stop –

This will stop running containers for the services defined in config file

$ docker-compose stop             ## Stop all containers
$ docker-compose stop web         ## Stop single container

restart –

This will restart containers of the services defined in config file

$ docker-compose restart           ## Restart all containers
$ docker-compose restart web       ## Restart single container

pause –

This will pause running containers for the services defined in the config file.

$ docker-compose pause            ## Pause all containers
$ docker-compose pause web        ## Pause single container

unpause –

This will start paused containers for the services defined in the config file.

$ docker-compose pause            ## Start all paused containers
$ docker-compose pause web        ## Start single paused container

rm –

This will remove stopped containers for the services defined in the config file.

$ docker-compose rm               ## Start all paused containers
$ docker-compose pause web        ## Start single paused container