Installing Docker and Docker Compose on Ubuntu

Why Docker?

Docker packages your application and all its dependencies into a portable container. You can run the same container on any server without worrying about environment differences, conflicting library versions, or complex setup scripts.

Step 1: Remove Old Docker Versions

apt remove docker docker-engine docker.io containerd runc 2>/dev/null

Step 2: Install Docker Engine

apt update
apt install ca-certificates curl gnupg -y

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

# Add the Docker 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" |   tee /etc/apt/sources.list.d/docker.list > /dev/null

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

Step 3: Run Docker Without sudo

usermod -aG docker $USER
newgrp docker

Step 4: Verify Installation

docker --version
docker compose version
docker run hello-world

Step 5: Enable Docker on Boot

systemctl enable docker
systemctl start docker

Your First Real Container — Nginx

# Run Nginx on port 80
docker run -d -p 80:80 --name webserver --restart unless-stopped nginx

# View running containers
docker ps

# View container logs
docker logs webserver

# Stop and remove
docker stop webserver
docker rm webserver

Docker Compose Example

Create docker-compose.yml:

version: '3.8'
services:
  web:
    image: nginx:latest
    ports:
      - "80:80"
    volumes:
      - ./html:/usr/share/nginx/html
    restart: unless-stopped

  db:
    image: mysql:8.0
    environment:
      MYSQL_ROOT_PASSWORD: strongpassword
      MYSQL_DATABASE: myapp
    volumes:
      - db_data:/var/lib/mysql
    restart: unless-stopped

volumes:
  db_data:

docker compose up -d      # Start in background
docker compose ps         # Check status
docker compose logs -f    # Follow logs
docker compose down       # Stop everything