flex_minecraft_instance.yaml

heat_template_version: 2018-08-31

description: >
  This Heat template provisions a virtual machine on OpenStack with a specified flavor, image, and SSH key, sets up a private network and subnet, configures routing to an external network, and installs a Minecraft Java server with the latest version. It includes security group rules to allow SSH and Minecraft server access, and assigns a floating IP to the instance for public accessibility.

parameters:
  flavor:
    type: string
    description: Flavor of the instance
    default: $FLAVOR_NAME
  image:
    type: string
    description: Image to use for the instance
    default: $IMAGE_ID
  key_name:
    type: string
    description: Name of the SSH key to use
    default: $KEY_NAME
  public_net_id:
    type: string
    description: ID of the public network
    default: $PUBLICNET_ID

resources:
  private_net:
    type: OS::Neutron::Net
    properties:
      name: private_net

  private_subnet:
    type: OS::Neutron::Subnet
    properties:
      network_id: { get_resource: private_net }
      cidr: "192.168.0.0/24"
      gateway_ip: "192.168.0.1"
      ip_version: 4
      dns_nameservers:
        - "8.8.8.8"
        - "8.8.4.4"

  router:
    type: OS::Neutron::Router
    properties:
      name: router
      external_gateway_info:
        network: { get_param: public_net_id }

  router_interface:
    type: OS::Neutron::RouterInterface
    properties:
      router_id: { get_resource: router }
      subnet_id: { get_resource: private_subnet }

  instance_port:
    type: OS::Neutron::Port
    properties:
      network_id: { get_resource: private_net }
      security_groups: [{ get_resource: instance_security_group }]

  instance_security_group:
    type: OS::Neutron::SecurityGroup
    properties:
      name: instance_security_group
      description: Security group for the instance
      rules:
        - direction: ingress
          ethertype: IPv4
          protocol: tcp
          port_range_min: 22
          port_range_max: 22
        - direction: ingress
          ethertype: IPv4
          protocol: icmp
        - direction: ingress
          ethertype: IPv4
          protocol: tcp
          port_range_min: 25565
          port_range_max: 25565

  floating_ip:
    type: OS::Neutron::FloatingIP
    properties:
      floating_network_id: { get_param: public_net_id }
      port_id: { get_resource: instance_port }

  instance:
    type: OS::Nova::Server
    properties:
      flavor: { get_param: flavor }
      image: { get_param: image }
      key_name: { get_param: key_name }
      networks:
        - port: { get_resource: instance_port }
      user_data:
        str_replace:
          template: |
            #!/bin/bash
            # Update and install necessary packages
            apt-get update -y
            apt-get install -y openjdk-17-jre-headless wget screen

            # Create a new user for the Minecraft server
            useradd -m -r -d /opt/minecraft minecraft

            # Download the latest Minecraft server
            su - minecraft -c "wget -O /opt/minecraft/minecraft_server.jar https://launcher.mojang.com/v1/objects/$(curl -s https://launchermeta.mojang.com/mc/game/version_manifest.json | jq -r '.latest.release')/server.jar"

            # Accept the EULA
            echo "eula=true" > /opt/minecraft/eula.txt

            # Create a systemd service for the Minecraft server
            cat <<EOF > /etc/systemd/system/minecraft.service
            [Unit]
            Description=Minecraft Server
            After=network.target

            [Service]
            User=minecraft
            Nice=5
            KillMode=none
            SuccessExitStatus=0 1
            ProtectHome=true
            ProtectSystem=full
            PrivateDevices=true
            NoNewPrivileges=true
            WorkingDirectory=/opt/minecraft
            ExecStart=/usr/bin/java -Xmx1024M -Xms1024M -jar minecraft_server.jar nogui
            ExecStop=/bin/kill -SIGINT \$MAINPID
            Restart=on-failure

            [Install]
            WantedBy=multi-user.target
            EOF

            # Reload systemd, enable and start the Minecraft service
            systemctl daemon-reload
            systemctl enable minecraft
            systemctl start minecraft
          params:
            "$FLAVOR_NAME": { get_param: flavor }
            "$IMAGE_ID": { get_param: image }
            "$KEY_NAME": { get_param: key_name }
            "$PUBLICNET_ID": { get_param: public_net_id }

outputs:
  instance_ip:
    description: IP address of the instance
    value: { get_attr: [floating_ip, floating_ip_address] }