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Step 18: Making your VM reachable via IPv4

Start

Now that your template has defined the full network and can reach the internet, you next need to ensure that the VM is reachable externally.

Floating-IP

Define a floating public IPv4 address, which is a resource with type OS::Neutron::FloatingIP.

Note that it is important to define the external network this IP is assigned from and the port this IP leads to:

heat_template_version: 2014-10-16

parameters:
    key_name:
        type: string
    public_network_id:
        type: string
        default: provider
resources:
    Instanz:
        type: OS::Nova::Server
        properties:
            key_name: { get_param: key_name }
            image: Ubuntu 16.04 Xenial Xerus - Latest
            flavor: m1.small
            networks:
                - port: {get_resource: Port }

    Netzwerk:
        type: OS::Neutron::Net
        properties:
            name: BeispielNetzwerk

    Port:
        type: OS::Neutron::Port
        properties:
            network: { get_resource: Netzwerk }

    Router:
        type: OS::Neutron::Router
        properties:
            external_gateway_info: { "network": { get_param: public_network_id }
            name: BeispielRouter

    Subnet:
        type: OS::Neutron::Subnet
        properties:
            name: BeispielSubnet
            dns_nameservers:
                - 8.8.8.8
                - 8.8.4.4
            network: { get_resource: Netzwerk }
            ip_version: 4
            cidr: 10.0.0.0/24
            allocation_pools:
            - { start: 10.0.0.10, end: 10.0.0.250 }

    Router_Subnet_Bridge:
        type: OS::Neutron::RouterInterface
        depends_on: Subnet
        properties:
            router: { get_resource: Router }
            subnet: { get_resource: Subnet }
 
    Floating_IP:
        type: OS::Neutron::FloatingIP
        properties:
            floating_network: { get_param: public_network_id }
            port_id: { get_resource: Port }

Security Groups

If you create a stack as outlined above, the VM would start but it would not be reachable. As previously stated, VMs do not receive traffic without a security group in place which explicitly allows this.

So, the logical next step is to create a resource with type OS::Neutron::SecurityGroup.

The security group must be defined to use the Port. On the resource itself, the rules are specified. These rules include the direction, port range, remote IP prefix, and protocol that these rules intend to allow.

heat_template_version: 2014-10-16

parameters:
    key_name:
        type: string
    public_network_id:
        type: string
        default: provider
resources:
    Instanz:
        type: OS::Nova::Server
        properties:
            key_name: { get_param: key_name }
            image: Ubuntu 16.04 Xenial Xerus - Latest
            flavor: m1.small
            networks:
                - port: {get_resource: Port }

    Netzwerk:
        type: OS::Neutron::Net
        properties:
            name: BeispielNetzwerk

    Port:
        type: OS::Neutron::Port
        properties:
            network: { get_resource: Netzwerk }
            security_groups: { get_resource: Sec_SSH }

    Router:
        type: OS::Neutron::Router
        properties:
            external_gateway_info: { "network": { get_param: public_network_id }
            name: BeispielRouter

    Subnet:
        type: OS::Neutron::Subnet
        properties:
            name: BeispielSubnet
            dns_nameservers:
                - 8.8.8.8
                - 8.8.4.4
            network: { get_resource: Netzwerk }
            ip_version: 4
            cidr: 10.0.0.0/24
            allocation_pools:
            - { start: 10.0.0.10, end: 10.0.0.250 }

    Router_Subnet_Bridge:
        type: OS::Neutron::RouterInterface
        depends_on: Subnet
        properties:
            router: { get_resource: Router }
            subnet: { get_resource: Subnet }


    Floating_IP:
        type: OS::Neutron::FloatingIP
        properties:
            floating_network: { get_param: public_network_id }
            port_id: { get_resource: Port }
 
    Sec_SSH:
        type: OS::Neutron::SecurityGroup
        properties:
            description: Diese Security Group erlaubt den eingehenden SSH-Traffic über Port22 und ICMP
            name: Ermöglicht SSH (Port22) und ICMP
            rules:
                - { direction: ingress, remote_ip_prefix: 0.0.0.0/0, port_range_min: 22, port_range_max: 22, protocol:tcp }
                - { direction: ingress, remote_ip_prefix: 0.0.0.0/0, protocol: icmp }

Conclusion

You can now create a stack that contains a single reachable instance.

In the next step, you will customize the instance using CloudConfig.