Docker-compose commands for container management

The docker-compose is a useful tool for orchestrating multi-container Docker applications. It allows us to run applications based on a YAML file. This file is a list of instructions that define the parameters of the launched applications. For example, we can run two containers – database MySQL and base web application WordPress. The docker-compose files might look like this:

version: '3.3'

services:
   db:
     image: mysql:5.7
     volumes:
       - db_data:/var/lib/mysql
     restart: always
     environment:
       MYSQL_ROOT_PASSWORD: somewordpress
       MYSQL_DATABASE: wordpress
       MYSQL_USER: wordpress
       MYSQL_PASSWORD: wordpress

   wordpress:
     depends_on:
       - db
     image: wordpress:latest
     ports:
       - "8000:80"
     restart: always
     environment:
       WORDPRESS_DB_HOST: db:3306
       WORDPRESS_DB_USER: wordpress
       WORDPRESS_DB_PASSWORD: wordpress
       WORDPRESS_DB_NAME: wordpress
volumes:
    db_data: {}

How to manage multi-container application?

To manage containers we can use a few basic docker-compose commands:

• Build or rebuild services

docker-compose build

• Create and start containers

docker-compose up

The containers have been run and logs printed on the console. To run in background use parameter -d.

• Run a one-off command on a service

docker-compose run <service> <bash_command>
ex: docker-compose run wordpress <service> <bash_command>

For example, print Debian version of a WordPress container.

• Show the list of containers running on a machine

docker ps

The above command presents the information about

• container id,
• image name and version,
• how long ago the container was created,
• status,
• ports and container name.

• Print list of information about running containers from current docker-compose.yaml

docker-compose ps

• Show all logs in container since its start

docker logs <service>

• Stop and remove containers, networks, volumes, and images created by the command “up”

docker-compose down

• Kill one or more running containers

docker kill <container_id>

• Show images list

docker images

• Execute a command in a running container

docker exec <service> <bash_command>

• Remove all unused data

docker system prune

Useful command combinations

• Kill all run containers

docker kill $(docker ps -q)

• Stop all run containers

docker stop $(docker ps -q)

• Remove all images

docker rmi $(docker images -q)

• Remove all containers

docker rm $(docker container ps -q)

Summary

Docker-compose is a useful and easy tool to manage multiple containers. You can decide how containers are separated, what resources they can use, and how they communicate with each other. You can also set what should happen if the status of one of the containers changes. This feature allows you to restore the state of the system automatically.

I invite you to explore the entire IoT analysis and management system.

If you have any question, leave it in the comment, I will be happy to answer 😉

References

[1] Official documentation https://docs.docker.com/compose/

[2] Quickstart: Compose and WordPress
https://docs.docker.com/compose/wordpress/