How to Deploy Docker & Docker Compose on Contabo VPS (Production Ready)

The Advantage of Running Docker on Contabo Cloud VPS

Docker has revolutionized production software engineering by encapsulating applications and their dependencies into self-sufficient containers. Because Contabo provides immense RAM at rock-bottom prices (8GB RAM on VPS 1 up to 64GB RAM on VPS 5), it is the ultimate budget cloud provider for running containerized homelabs, web apps, Ghost blogs, Redis caches, and PostgreSQL databases.

Step 1: Removing Unofficial Old Packages

Ubuntu repositories often carry older forks under docker.io. Ensure your system starts with a clean slate:

sudo apt remove -y docker docker-engine docker.io containerd runc

Step 2: Installing Docker via Official Repository

Always install directly from Docker Inc.'s official upstream repository to receive the latest security patches:

# Install prerequisite certificates
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

# Set up the stable 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 Engine, CLI, and Docker Compose plugin
sudo apt update
sudo apt install -y docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

Step 3: Managing Docker as a Non-Root User

Avoid executing docker commands with sudo by adding your active user to the docker group:

sudo usermod -aG docker $USER
newgrp docker

# Verify installation without sudo
docker run --rm hello-world

Step 4: Critical Security Fix: Docker vs. UFW Firewall

Warning: By default, the Docker daemon modifies iptables directly, allowing exposed ports (e.g. -p 8080:8080) to bypass your UFW firewall completely! To fix this security vulnerability, configure Docker daemon log rotation and iptables handling.

Create or edit /etc/docker/daemon.json:

sudo nano /etc/docker/daemon.json

Paste the following production configuration:

{
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "20m",
    "max-file": "3"
  },
  "live-restore": true
}

Reload Docker to apply changes:

sudo systemctl restart docker

Step 5: Deploying a Multi-Container Stack with Docker Compose

Let us create a production-grade Nginx web application with automatic restarts:

mkdir -p ~/stacks/webapp && cd ~/stacks/webapp
nano docker-compose.yml

Add the following Docker Compose configuration:

services:
  web:
    image: nginx:alpine
    container_name: production_nginx
    restart: unless-stopped
    ports:
      - "80:80"
    volumes:
      - ./html:/usr/share/nginx/html:ro
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost"]
      interval: 30s
      timeout: 5s
      retries: 3

Create a sample web page:

mkdir html
echo "<h1>Docker Running on Contabo High-RAM VPS</h1>" > html/index.html

Launch the container in detached background mode:

docker compose up -d

Step 6: Setting Up Docker System Pruning & Log Rotation

Dangling container images and build caches can silently consume tens of gigabytes of disk space over time. Set up an automated weekly cron job to prune unused containers and build artifacts:

# Create maintenance cron
sudo crontab -e
# Add line: run docker prune every Sunday at 3 AM
0 3 * * 0 /usr/bin/docker system prune -af --volumes > /dev/null 2>&1

Step 7: Frequently Asked Questions (FAQ)

Can I run Portainer or Traefik with Docker on Contabo?

Yes! Contabo's full KVM virtualization supports Portainer CE, Traefik v3 reverse proxies, and Nginx Proxy Manager with automated SSL certificates.

How many Docker containers can I run on Contabo Cloud VPS 1?

With 4 vCPU cores and 8GB RAM, you can comfortably host 15 to 25 typical lightweight containers (such as Ghost, Redis, Vaultwarden, Postgres, and Nginx) without performance degradation.