swarm-cloud-init.yml

#cloud-config

# 1. System update
package_update: true
package_upgrade: true

# 2. Package installation
packages:
  - ca-certificates
  - curl
  - gnupg
  - ufw

# 3. SSH configuration (Port 8899)
write_files:
  - path: /etc/ssh/sshd_config.d/99-custom-port.conf
    permissions: '0644'
    content: |
      Port 8899

# 4. Run commands
runcmd:
  # --- OFFICIAL DOCKER INSTALLATION ---
  - 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
  - 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
  - apt-get update
  - apt-get install -y docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

  # --- FIREWALL CONFIGURATION (UFW) ---
  # IMPORTANT: We open the NEW SSH port (8899) before enabling the firewall
  - ufw allow 8899/tcp comment 'SSH Custom Port'

  # Web ports (Traefik)
  - ufw allow 80/tcp    comment 'HTTP Traefik'
  - ufw allow 443/tcp   comment 'HTTPS Traefik'

  # Docker Swarm ports (Cluster Internal)
  - ufw allow 2377/tcp  comment 'Swarm Manager'
  - ufw allow 7946/tcp  comment 'Swarm Node Comm TCP'
  - ufw allow 7946/udp  comment 'Swarm Node Comm UDP'
  - ufw allow 4789/udp  comment 'Swarm Overlay Network'

  # Enable firewall
  - ufw --force enable

  # --- APPLY SSH CONFIG ---
  # Restart SSH service to apply the new port 8899
  - systemctl restart ssh

  # --- START DOCKER ---
  - systemctl enable docker
  - systemctl start docker

final_message: "Server ready. SSH is listening on port 8899. Docker installed."