Install Docker and Docker Compose on Linux

Use at your own risk. All guides and scripts are provided for educational purposes only. Always review and understand any code before running it — especially with administrative privileges. Test in a safe environment before using in production. Your system, your responsibility.

Docker lets you run applications in isolated containers. Docker Compose lets you manage multiple containers at once — for example a web app, a database, and a cache — using a single file and a single command.

This guide covers installation on Ubuntu and Debian, fixing permissions so you don’t need to type sudo every time, and setting up a clean folder structure for your containers.

Requirements

Ubuntu 20.04+ or Debian 11+
A user account with sudo privileges
An internet connection

Step 1 – Install Docker Engine

Add Docker’s official repository and install:

# Update and install dependencies
sudo apt update
sudo apt install -y ca-certificates curl gnupg

# Add Docker's official GPG key
sudo install -m 0755 -d /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | \
  sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
sudo chmod a+r /etc/apt/keyrings/docker.gpg

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

# Install Docker
sudo apt update
sudo apt install -y docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

On Debian, replace ubuntu with debian in the repository URL above.

Step 2 – Verify the Installation

docker --version
docker compose version

You should see something like:

Docker version 26.x.x
Docker Compose version v2.x.x

Step 3 – Fix Permissions (No More sudo)

By default, Docker requires root privileges. Add your user to the docker group to fix this:

sudo usermod -aG docker $USER
newgrp docker

Verify it works without sudo:

docker run hello-world

If you see a welcome message without any errors — you’re all set.

Adding your user to the docker group gives that user root-equivalent access to the system. This is fine for a lab environment, but keep it in mind for production systems.

Step 4 – Organize Your Containers

A clean folder structure makes managing many containers much easier, especially as your lab grows.

Recommended structure:

~/docker/
├── nginx/
│   ├── compose.yml
│   └── config/
├── nextcloud/
│   ├── compose.yml
│   └── data/
├── monitoring/
│   ├── compose.yml
│   └── prometheus.yml
└── databases/
    ├── compose.yml
    └── init/

Each service gets its own folder with its own compose.yml. This means you can start, stop, and manage each service independently without affecting the others.

Step 5 – Example compose.yml

Here is a simple example running Nginx:

# ~/docker/nginx/compose.yml

services:
  nginx:
    image: nginx:latest
    container_name: my-nginx
    ports:
      - "8080:80"
    volumes:
      - ./config/nginx.conf:/etc/nginx/nginx.conf:ro
      - ./html:/usr/share/nginx/html:ro
    restart: unless-stopped

Start the service:

cd ~/docker/nginx
docker compose up -d

Useful Commands

Command	What it does
`docker compose up -d`	Start containers in the background
`docker compose down`	Stop and remove containers
`docker compose restart`	Restart containers
`docker compose logs -f`	Follow live logs
`docker compose pull`	Pull the latest image
`docker ps`	List running containers
`docker ps -a`	List all containers including stopped
`docker stats`	Real-time CPU and memory usage
`docker system prune`	Clean up unused resources

Tips

Use named volumes for persistent data:

volumes:
  db-data:

services:
  postgres:
    image: postgres:16
    volumes:
      - db-data:/var/lib/postgresql/data

Store sensitive values in a .env file:

# ~/docker/databases/.env
POSTGRES_PASSWORD=yourpassword
POSTGRES_USER=admin

# compose.yml reads .env automatically
services:
  postgres:
    environment:
      POSTGRES_PASSWORD: ${POSTGRES_PASSWORD}
      POSTGRES_USER: ${POSTGRES_USER}

Add .env to .gitignore if you use Git — never push passwords to a repository.