dnsaas-bind.yml

    # define a number of public interface IP which live outside of the
    # dynamic inventory. This is necessary as we must know and fix these
    # IP as they must be referenced outside our deployment
    # put as many entries in this list as dnsaas_bind hosts, index in host group
    # will select which is used per host.
    dnsaas_bind_public_interfaces:
       - infrastructure_address: {
             "address": "172.29.64.17", 
             "bridge": "br-external", 
             "interface": "eth20", 
             "netmask": "255.255.255.224", 
             "static_routes": [
                 {
                     "cidr": "172.29.65.0/24", 
                     "gateway": "172.29.64.5"
                 }
             ], 
             "type": "veth"
          }
       - infrastructure_address: {
              "address": "172.29.64.18", 
              "bridge": "br-external", 
              "interface": "eth20", 
              "netmask": "255.255.255.224", 
              "static_routes": [
                  {
                      "cidr": "172.29.65.0/24", 
                      "gateway": "172.29.64.5"
                  }
              ], 
              "type": "veth"
          }

    # find the index for this host in the host group
    dnsaas_bind_host_group_index: "{{ groups['dnsaas-bind'].index(inventory_hostname) }}"

    # we will clobber the existing default interface unless we preserve it
    dnsaas_bind_lxc_container_networks_default:
      lxcbr0_address:
        bridge: lxcbr0
        interface: eth0
        type: veth

    # combine the default interface with the specific external interface for this host
    lxc_container_networks: "{{ dnsaas_bind_lxc_container_networks_default | combine(dnsaas_bind_public_interfaces[dnsaas_bind_host_group_index | int]) }}"