Docker’s Compose tool is an ideal tool for working in the development and testing environments, but also for small production applications. This article explains how to easily orchestrate Docker applications with Compose on Ubuntu.
Docker Compose under Ubuntu: prerequisites
Before you can use Docker Compose, make sure your system meets the following requirements:
- DockerEngine : as Compose is an extension of Docker Engine, you must install it;
- Operating system : Ubuntu, sudo user with root privileges.
Do you want to use an operating system other than Linux? Check out our guide on how to install Docker Compose on Windows and Docker Compose on macOS.
Install Docker Compose on Ubuntu step by step
To use Docker Compose on Ubuntu, you must first install the DockerEngine on your system and verify that it is running correctly. Once Docker is running, download Compose and create the YAML file to configure your applications.
Step 1: Download and install Docker Compose
Download the latest version of Docker Compose from the official repository GitHub by typing the following command in a terminal:
$ curl -SL https://github.com/docker/compose/releases/download/v2.17.2/docker-compose-linux-x86_64 -o /usr/local/bin/docker-composeshell
You must then grant Docker Compose the performance rights :
$ sudo chmod +x /usr/local/bin/docker-composeshell
The “–version” option allows you to verify that Compose has been installed correctly.
$ docker-compose --versionshell
Here is the output displayed:
If the installation fails, take a look at the path and verify that it is the correct one.
It is also possible to create a symbolic link towards the path /usr/bin :
$ sudo ln -s /usr/local/bin/docker-compose /usr/bin/docker-composeshell
Step 2: Configure the docker-compose.yml file
To explain file design Docker-Compose-YAMLwe use the Nginx image from the official Docker hub for the container environment.
First create a new folder in your home directory:
$ mkdir ~/compose-testshell
Go to the directory and create a new folder there for the root directory of your environment Nginx.
$ cd ~/compose-test
$ mkdir appshell
You can use any text editor like nano to create a index.html.
$ nano app/index.htmlshell
Here is the HTML code of a test page:
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Docker Compose Test</title>
</head>
<body>
<h1>This is a Docker Compose Test Page for an Nginx container.</h1>
</body>
</html>html
Save and close the HTML file then create docker-compose.yml.
$ nano docker-compose.ymlshell
The contents consist of the configuration version number and the Services block.
version: ‘3.9’
services:
web:
image: nginx:alpine
ports:
- "8000:80"
volumes:
- ./app:/usr/share/nginx/htmlYAML
In the Services block, only the “web” service is listed. Next comes the Nginx image used and the port forwarding. In this case, all requests on port 8000 of the host machine are redirected to the web container on port 80, on which Nginx is running. Additionally, we use a volume shared between host and container which allows the Nginx application to access the local “app” folder.
Step 3: Run Docker Compose
The following command creates a web container and run the container environment in the background:
$ docker-compose up -dshell
If the image specified in the YAML file is not available on the local system, it is automatically downloaded.
To test that the Nginx environment is working correctly, type the command ps.
The test page created previously is now accessible on localhost:8000 if you run the demo locally on your computer. If you’re going through a remote server, just provide your server’s IP address instead of « localhost ».
The command stopallows you to exit the container application again.
$ docker-compose stopshell
