Installation and Usage Guide for Docker on Ubuntu

Docker is a powerful tool that enables developers to build, test, and deploy applications quickly inside lightweight, portable containers. This guide will walk you through the process of installing Docker on an Ubuntu system and provide some basic commands to get you started.

Prerequisites

• Ubuntu version: This guide works for Ubuntu 20.04, 22.04, or newer.
• User privileges: You need
  sudo
  or root access to install and configure Docker.

Step 1: Update System Packages

Before installing Docker, it’s important to update your system packages to ensure you have the latest versions:

Step 2: Install Docker

2.1. Install Required Packages

Install packages that allow

to use repositories over HTTPS:

2.2. Add Docker’s Official GPG Key

Add the Docker GPG key to verify package authenticity:

2.3. Add Docker Repository

Add the Docker repository to

sources:

2.4. Install Docker

Now, update the package index and install Docker:

This command installs Docker Community Edition (CE) and other required components.

Step 3: Verify Docker Installation

Check that Docker is installed and running correctly:

You should see output indicating that Docker is active and running.

To verify the installation further, run the following command:

You can also run the

container, which is a simple test to confirm Docker is functioning correctly:

This command will download a test image and run it in a container. If everything is set up correctly, you will see a “Hello from Docker!” message.

Step 4: Manage Docker as a Non-root User

By default,

commands need to be run with. To avoid this, add your user to the group:

After running this command, log out and log back in, or restart your terminal session to apply the changes.

To test if Docker now works without

, run:

Step 5: Basic Docker Commands

Here are some basic commands to help you start using Docker:

• Pull an Image: Download a Docker image from Docker Hub.
  docker pull ubuntu:latest

• Run a Container: Run an Ubuntu container interactively.
  docker run -it ubuntu

• List Running Containers: Display active containers.
  docker ps

• List All Containers: Show all containers, including stopped ones.
  docker ps -a

• Stop a Container: Stop a running container.
  docker stop <container_id>

• Remove a Container: Delete a stopped container.
  docker rm <container_id>

• Remove an Image: Delete a Docker image from your system.
  docker rmi ubuntu:latest


Step 6: Using Docker Compose

Docker Compose is a tool for defining and running multi-container Docker applications using a

file.

6.1. Create a

docker-compose.yml

File

Create a new directory for your Docker Compose project:

Create a

file with the following content:

This file defines a simple Nginx web server that will run on port 8080.

6.2. Start the Docker Compose Application

Run the following command to start the services defined in

:

The

flag runs the container in detached mode, meaning it runs in the background.

6.3. Verify the Service

Visit

in your web browser. You should see the default Nginx welcome page.

6.4. Stop the Docker Compose Application

To stop and remove the services, run:

Step 7: Update Docker

To keep Docker up to date, use the following commands periodically:

Conclusion

You have successfully installed Docker and Docker Compose on Ubuntu, and you’ve learned some basic commands to get started. Docker simplifies the deployment of applications by packaging them in containers, making it easier to manage dependencies and ensure consistency across different environments. With Docker up and running, you can explore more advanced features like creating custom Docker images, networking, and orchestration tools like Kubernetes for scaling your applications.