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How to Use Docker Compose

In this article we will try to teach you how to Use Docker Compose. Developing applications with Docker can get tricky when juggling multiple services and containers. Learn more about Docker Compose, the tool that allows you to run multi-container application environments. An application can consist of multiple containers running different services. It can be tedious to start and manage containers manually, so Docker has developed a useful tool to help speed up the process – Docker Compose.

Docker Compose is software used to define and run multi-container Docker applications. It can handle multiple containers at the same time in the production, staging, development, test and CI environment. Therefore, use Docker Compose to manage the entire Software Development Lifecycle (SDLC).

Docker Compose works by applying rules defined in a docker-compose.yaml file. The YAML file configures the application’s services and contains rules that specify how they should run. If the file exists, you can start, stop, or rebuild all services with a single command. In addition, you can check the status of a service, view log output, and run one-time commands. Below we have mention the steps to Use Docker Compose.

Use Docker Compose

Install Docker Compose

Step 1: Download the latest version of Docker Compose. Check the releases page and replace 1.25.4 in the command below with the version tagged as Latest release:

sudo curl -L https://github.com/docker/compose/releases/download/1.25.4/docker-compose-`uname -s`-`uname -m` -o /usr/local/bin/docker-compose

Step 2: Set file permissions:

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

Basic Usage

This section will review an example Docker Compose file taken from the Docker official documentation.

Step 1: Open docker-compose.yml in a text editor and add the following content:

version: ‘3’

services:db:image: mysql:5.7volumes:– db_data:/var/lib/mysqlrestart: alwaysenvironment:MYSQL_ROOT_PASSWORD: somewordpressMYSQL_DATABASE: wordpressMYSQL_USER: wordpressMYSQL_PASSWORD: wordpress

wordpress:depends_on:– dbimage: wordpress:latestports:– “8000:80”restart: alwaysenvironment:WORDPRESS_DB_HOST: db:3306WORDPRESS_DB_USER: wordpressWORDPRESS_DB_PASSWORD: wordpressvolumes:db_data:

Step 3: Save the file and run Docker Compose from the same directory:

docker-compose up -d

Step 4: You now have a WordPress container and MySQL container running on your host. Navigate to 192.0.8.1:8000/wordpress in a web browser to see your newly installed WordPress application. You can also use docker ps to further explore the resulting configuration:

docker ps

Step 5: Stop and remove the containers:

docker-compose down

Build an Application from Scratch

Create a docker-compose.yml file one section at a time to illustrate the steps of building a multi-container application.

Define a Simple Service:

Step 1: Create a new docker-compose.yml in a text editor and add the following content:

file: docker-compose.yml

Step 2: Bring up your container:

docker-compose up -d

Step 3: Check the status of your container:

docker ps

Step 4: Bring down the container:

docker-compose down

Add Additional Services

Step 1: Reopen docker-compos.yml and add the database service below:

file: docker-compose.yml

There are now two services defined:

The Distro service is the same as before. The database server contains the instructions for a postgres container, and the directives: volumes: – ../dumps:/tmp and ports:-“5432:5432”, the first directive maps the containerd /dumps folder to our local /tmp folder. The second directive maps the containers ports to the local host’s ports.

Step 2: Check the running containers:

docker ps

Step 3: Bring down both containers:

docker-compose down

Add an nginx Service

Step 1: Add an nginx container so that your application will be able to serve websites:

file: docker-compose.yml

Step 2: Start Docker Compose and check the container status:

docker-compose up -ddocker ps

Step 3: Test nginx by navigating to your Linode’s public IP address, port 8080 in a browser (for example 192.0.2.0:8080). You should see the default nginx landing page displayed.

Persistent Data Storage

It is important to set up a persistent volume on the host that the database containers will use to store their data.

Step 1: Add a volumes section to docker-compose.yml and edit the database service to refer to the volume:

file: docker-compose.yml

Step 2: external: true tells Docker Compose to use a pre-existing external data volume. If no volume named data is present, starting the application will cause an error. Create the volume:

docker volume create –name=data

Step 3: Start the application as before:

docker-compose up -d

Final Words

We hope our article on how to use Docker Compose will help you and resolve all your problems. Docker Compose allows you to host multiple isolated environments on one host. Running everything on a single piece of hardware can save you a lot of resources. Its features of allowing it to cache a configuration and reuse existing containers also contribute to resource efficiency. If you also want to use Docker Compose then follow the steps mentioned above.

I hope you understand this article, how to Use Docker Compose.

James Hogan
James Hogan is a senior staff writer at Bollyinside, where he has been covering various topics, including laptops, gaming gear, keyboards, storage, and more. During that period, they evaluated hundreds of laptops and thousands of accessories and built a collection of entirely too many mechanical keyboards for their own use.

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