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Getting Started with Docker

What You'll Learn

How to install Docker CE, configure it for a homelab environment, and establish good patterns from the start.

Installation

# Remove old versions
sudo apt remove docker docker-engine docker.io containerd runc 2>/dev/null

# Add Docker's official GPG key and repo
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

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

# Add your user to docker group
sudo usermod -aG docker $USER

curl -fsSL https://get.docker.com | sh
sudo usermod -aG docker $USER

Warning

The convenience script is fine for lab environments but not recommended for production.

Post-Install Configuration

Configure Docker Daemon

/etc/docker/daemon.json
{
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "10m",
    "max-file": "3"
  },
  "default-address-pools": [
    {
      "base": "172.20.0.0/16",
      "size": 24
    }
  ],
  "metrics-addr": "0.0.0.0:9323",
  "experimental": true
}

Why This Matters

  • Log rotation prevents Docker from eating all your disk space
  • Custom address pools avoid conflicts with your LAN subnets
  • Metrics endpoint enables Prometheus scraping for monitoring

First Compose Stack

docker-compose.yml
services:
  whoami:
    image: traefik/whoami
    container_name: whoami
    ports:
      - "8080:80"
    restart: unless-stopped

docker compose up -d
curl http://localhost:8080

If you see output with container details, you're in business.

Next Steps

  • Set up a reverse proxy (Traefik or Nginx Proxy Manager)
  • Deploy your first real service
  • Establish a backup strategy for container data
  • Set up monitoring with Prometheus + Grafana