OpenStack - Split Public API & Floating IP networks

By default in RDO Manager/ RH-OSP, Public API and Floating IP are set in the same subnet.
In some case, it will be useful to split these networks into different subnets and interfaces.
One option is to dedicate a nic for the External network (Public API) and mount a bridge on an other nic for Floating IP:

1. Apply change in YAML controller file:

    type: OS::Heat::StructuredConfig
      group: os-apply-config
          - type: ovs_bridge
            name: {get_input: bridge_name}
            mtu: 9000
             - type: interface
               name: nic5
               mtu: 9000
          - type: interface
            name: nic7
            mtu: 9000
             - ip_netmask: {get_param: ExternalIpSubnet}
             - ip_netmask:
               next_hop: {get_param: ExternalInterfaceDefaultRoute}

2. Check the result on controller nodes:

After deployment, you have two specific interfaces on controller nodes:

[root@ctlr000 ~]# ip a
eth6: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9000 qdisc pfifo-fast state UP qlen 1000
    link/ether 52:54:00:92:0f:bc brd ff:ff:ff:ff:ff:ff
    inet brd scope global eth6
       valid_lft forever preferred-lft forever
    inet brd scope global eth6
       valid_lft forever preferred-lft forever
    inet6 fe80::5054:ff:fe92:fbc/64 scope link
       valid_lft forever preferred-lft forever
10: br-ex: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9000 qdisc noqueue state UNKNOWN
    link/ether a2:23:80:61:b3:4d brd ff:ff:ff:ff:ff:ff
    inet6 fe80::a023:80ff:fe61:b34d/64 scope link
       valid_lft forever preferred_lft forever

For this example: eth6 is dedicated for Public API & VIP and br-ex for Floating IPs

3. Create network with neutron

Once interfaces are up and running, the last step is to create network with neutron CLI and bind it on our bridge:

neutron net-create fip-1 --router:external --provider:network_type flat 
--provider:physical_network datacentre
neutron subnet-create --name fip-1 --disable-dhcp --allocation-pool start=,end= \
 --gateway nova

Guillaume Chenuet

Make it simple, but significant.