Background

In previous versions of Rhel Osp 7 the Control Plane/Provisioning network Interface was assigned via DHCP and not managed via Heat. Starting in 7.2, this interface is now managed via Heat.

Sample Heat Template

Below is an example from /home/stack/templates/nic-configs/compute.yaml or /home/stack/templates/nic-configs/controller.yaml. In this example we are hard coding the interface name, however this is not required (although I recommend it).

resources:
  OsNetConfigImpl:
    type: OS::Heat::StructuredConfig
    properties:
      group: os-apply-config
      config:
        os_net_config:
          network_config:
            -
              type: interface
              name: em3
              use_dhcp: false
              addresses:
                -
                  ip_netmask:
                    list_join:
                      - '/'
                      - - {get_param: ControlPlaneIp}
                        - {get_param: ControlPlaneSubnetCidr}
              routes:
                -
                  ip_netmask: 169.254.169.254/32
                  next_hop: {get_param: EC2MetadataIp}

Note that this new configuration requires an additional parameter to be added to your top-level template, usually named network-environment.yaml.

ControlPlaneSubnetCidr: "23"

Stick this next to the “ControlPlaneIP” under “parameter_defaults”

  ControlPlaneSubnetCidr: "23"
  ControlPlaneDefaultRoute: 172.99.99.1

Note that if you forget to add this param, the network CIDR for this network will default to “24” which may or may not be correct for your environment. So watch out.