Run Multi-container apps with Docker Compose

#docker #devops #linux #tutorial

Containerization of apps is a fast-growing practice as many companies are embracing the cloud and DevOps concepts. Docker packages an application, libraries, and its dependencies in a virtual container that can run on any server. Being that most applications do not run on one single component (even dinosaur apps 🦖 have frontend and backend components), we need a way to define and manage multi-container apps.

In this tutorial I will utilize Docker compose to get a blog up and running that consists of a Ghost Blog service and a MYSQL service; both services will use volumes for persistent storage. This tutorial assumes you have working knowledge of Docker and a server with Docker and Docker compose installed.

What is Docker Compose?

Compose is a file format for describing distributed Docker apps, and it’s a tool for managing them.

What is Ghost?

Ghost is a free and open source blogging platform written in Javascript.

Let’s go! 🐳

Step 1 — Login to the server and become root

1. SSH into the server and become root

ssh <username>@PUBLIC_IP_ADDRESS

sudo su -

Step 2 — Create a Ghost Blog and MySQL service

2. Create a docker-compose.yml file in the root directory

vi docker-compose.yml

Add the following contents

version: '3'
services:
  ghost:
    image: ghost:1-alpine
    container_name: ghost-blog
    restart: always
    ports:
      - 80:2368
    environment:
      database__client: mysql
      database__connection__host: mysql
      database__connection__user: root
      database__connection__password: P4sSw0rd0!
      database__connection__database: ghost
    volumes:
      - ghost-volume:/var/lib/ghost
    depends_on:
      - mysql

  mysql:
    image: mysql:5.7
    container_name: ghost-db
    restart: always
    environment:
      MYSQL_ROOT_PASSWORD: P4sSw0rd0!
    volumes:
      - mysql-volume:/var/lib/mysql

volumes:
  ghost-volume:
  mysql-volume: