Install Docker on Ubuntu 24.04|22.04 [Step-by-Step]

Docker is the standard container runtime for building, shipping, and running applications in isolated environments. It packages your application with all its dependencies into a container that runs consistently across any Linux system.

Original content from computingforgeeks.com - post 154427

This guide covers installing Docker Engine 29.x from the official Docker repository on Ubuntu 24.04 or 22.04, then walks through building images, running containers, and managing multi-container applications with Docker Compose.

Prerequisites

A server or desktop running Ubuntu 24.04 or 22.04 LTS
Root or sudo access
Internet access to pull images from Docker Hub

Step 1: Update System Packages

Update your package index and install any available upgrades:

sudo apt update && sudo apt -y upgrade

Reboot if a kernel update was applied:

[ -f /var/run/reboot-required ] && sudo reboot -f

Step 2: Add Docker APT Repository

Ubuntu’s default repositories include an older docker.io package. For the latest Docker Engine, add the official Docker repository.

Install the prerequisites and download Docker’s GPG signing key:

sudo apt install -y ca-certificates curl
sudo install -m 0755 -d /etc/apt/keyrings
sudo curl -fsSL https://download.docker.com/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.asc
sudo chmod a+r /etc/apt/keyrings/docker.asc

Add the Docker repository. This command automatically detects your Ubuntu version codename:

echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/ubuntu $(. /etc/os-release && echo "$VERSION_CODENAME") stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

Update the package index to include packages from the new repository:

sudo apt update

Step 3: Install Docker Engine

Install Docker Engine, the CLI, containerd, and the Buildx and Compose plugins:

sudo apt install -y docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

Verify the installed versions:

docker --version

You should see Docker Engine 29.x confirmed:

Docker version 29.3.0, build 5927d80

Check the Docker Compose plugin version:

docker compose version

Compose v5.x should be available:

Docker Compose version v5.1.1

Step 4: Allow Non-Root User to Run Docker

By default, Docker commands require sudo. Add your user to the docker group to run Docker without sudo:

sudo usermod -aG docker $USER
newgrp docker

The newgrp command activates the group membership in your current shell without requiring a logout. Verify it works by running a test container:

docker run --rm hello-world

If Docker is working correctly, you will see “Hello from Docker!” in the output confirming the installation is successful.

Step 5: Run Your First Container

Pull and run an Nginx web server container, mapping port 8080 on the host to port 80 inside the container:

docker run -d --name web -p 8080:80 nginx:alpine

The -d flag runs the container in the background. Check that it is running:

docker ps

The container list shows Nginx running on port 8080:

CONTAINER ID   IMAGE          COMMAND                  CREATED         STATUS         PORTS
a1b2c3d4e5f6   nginx:alpine   "/docker-entrypoint.…"   5 seconds ago   Up 5 seconds   0.0.0.0:8080->80/tcp

Test access to the container with curl:

curl -s localhost:8080 | head -5

You should see the default Nginx welcome page HTML, confirming the container is serving traffic.

Step 6: Build a Custom Docker Image

Create a project directory and a Dockerfile for a simple Apache web server:

mkdir ~/docker-demo && cd ~/docker-demo

Create the Dockerfile:

vi Dockerfile

Add the following instructions that build an Apache image from the official Debian base:

FROM debian:bookworm-slim

LABEL maintainer="[email protected]"

RUN apt-get update && \
    apt-get install -y --no-install-recommends apache2 && \
    rm -rf /var/lib/apt/lists/*

RUN echo "Hello from Docker on Ubuntu" > /var/www/html/index.html

EXPOSE 80

CMD ["apachectl", "-D", "FOREGROUND"]

Build the image and tag it:

docker build -t my-apache:latest .

List your local images to confirm it was built:

docker images

The output shows your new image alongside the Nginx image pulled earlier:

REPOSITORY   TAG       IMAGE ID       CREATED          SIZE
my-apache    latest    abc123def456   5 seconds ago    180MB
nginx        alpine    def456abc789   2 weeks ago      50MB

Run a container from your custom image:

docker run -d --name my-web -p 8081:80 my-apache:latest

Test it:

curl localhost:8081

The response should return the custom message from the Dockerfile:

Hello from Docker on Ubuntu

Step 7: Multi-Container Apps with Docker Compose

Docker Compose lets you define and run multi-container applications from a single YAML file. Create a project that runs Nginx with a Redis cache:

mkdir ~/compose-demo && cd ~/compose-demo
mkdir html

Create a simple HTML page:

echo '<h1>Docker Compose is running</h1>' > html/index.html

Create the Compose file:

vi compose.yaml

Define two services – a web server and a Redis instance:

services:
  web:
    image: nginx:alpine
    ports:
      - "8090:80"
    volumes:
      - ./html:/usr/share/nginx/html:ro

  redis:
    image: redis:alpine
    ports:
      - "6379:6379"

Start all services in the background:

docker compose up -d

Check the running containers:

docker compose ps

Both services should show as running:

NAME                    IMAGE          SERVICE   STATUS         PORTS
compose-demo-redis-1    redis:alpine   redis     Up 3 seconds   0.0.0.0:6379->6379/tcp
compose-demo-web-1      nginx:alpine   web       Up 3 seconds   0.0.0.0:8090->80/tcp

Test the web service:

curl localhost:8090

The response confirms Compose is working:

<h1>Docker Compose is running</h1>

Stop and remove all containers when done:

docker compose down

Essential Docker Commands Reference

Here are the most common Docker commands you will use daily:

Command	Description
`docker ps`	List running containers
`docker ps -a`	List all containers including stopped
`docker images`	List local images
`docker logs CONTAINER`	View container logs
`docker exec -it CONTAINER bash`	Open a shell inside a running container
`docker stop CONTAINER`	Stop a running container
`docker rm CONTAINER`	Remove a stopped container
`docker rmi IMAGE`	Remove a local image
`docker system prune -a`	Remove all unused images, containers, and networks
`docker compose up -d`	Start Compose services in background
`docker compose down`	Stop and remove Compose services

Conclusion

Docker Engine 29.x and Compose v5.x are running on your Ubuntu system. You can now build images, run containers, and orchestrate multi-container applications.

For production deployments, consider setting up a private Docker registry for your images, configuring log rotation for container logs, and exploring Ansible for managing Docker containers at scale.