---
title: Floating IPs
---

networking-calico includes beta support for floating IPs.  Currently this
requires running Calico as a Neutron core plugin (i.e. `core_plugin =
calico`) instead of as an ML2 mechanism driver.

> **Note:** We would like it to work as an ML2 mechanism driver too - patches
> and/or advice welcome!

To set up a floating IP, you need the same pattern of Neutron data model
objects as you do for Neutron in general, which means:

- a tenant network, with an instance attached to it, that will be the target of
  the floating IP

- a Neutron router, with the tenant network connected to it

- a provider network with `router:external True` that is set as the
  router's gateway (e.g. with `neutron router-gateway-set`), and with a
  subnet with a CIDR that floating IPs will be allocated from

- a floating IP, allocated from the provider network subnet, that maps onto the
  instance attached to the tenant network.

For example:

    # Create tenant network and subnet
    neutron net-create --shared calico
    neutron subnet-create --gateway 10.65.0.1 --enable-dhcp --ip-version 4 --name calico-v4 calico 10.65.0.0/24

    # Boot a VM on that network, and find its Neutron port ID.
    nova boot [...]
    neutron port-list

    # Create external network and subnet - this is where floating
    # IPs will be allocated from.
    neutron net-create public --router:external True
    neutron subnet-create public 172.16.1.0/24

    # Create a router connecting the tenant and external networks.
    neutron router-create router1
    neutron router-interface-add router1 <tenant-subnet-id>
    neutron router-gateway-set router1 public

    # Create a floating IP and associate it with the target VM.
    neutron floatingip-create public
    neutron floatingip-associate <floatingip-id> <target-VM-port-id>

Then the Calico agents will arrange that the floating IP is routed to the
instance's compute host, and then DNAT'd to the instance's fixed IP address:

    core@compute-node01:~$ ip r
    default via 10.240.0.1 dev eth0
    10.65.0.13 dev tap9a7e0868-da  scope link
    10.65.0.14 via 192.168.8.4 dev l2tpeth8-3  proto bird
    10.65.0.23 via 192.168.8.4 dev l2tpeth8-3  proto bird
    10.240.0.1 dev eth0  scope link
    172.16.1.3 dev tap9a7e0868-da  scope link
    192.168.8.0/24 dev l2tpeth8-3  proto kernel  scope link  src 192.168.8.3
    192.168.122.0/24 dev virbr0  proto kernel  scope link  src 192.168.122.1

    core@compute-node01:~$ sudo iptables -L -n -v -t nat
    [...]
    Chain felix-FIP-DNAT (2 references)
     pkts bytes target     prot opt in     out     source               destination
        0     0 DNAT       all  --  *      *       0.0.0.0/0            172.16.1.3           to:10.65.0.13

    Chain felix-FIP-SNAT (1 references)
     pkts bytes target     prot opt in     out     source               destination
        0     0 SNAT       all  --  *      *       10.65.0.13           10.65.0.13           to:172.16.1.3

    Chain felix-OUTPUT (1 references)
     pkts bytes target     prot opt in     out     source               destination
        1    60 felix-FIP-DNAT  all  --  *      *       0.0.0.0/0            0.0.0.0/0

    Chain felix-POSTROUTING (1 references)
     pkts bytes target     prot opt in     out     source               destination
        1    60 felix-FIP-SNAT  all  --  *      *       0.0.0.0/0            0.0.0.0/0

    Chain felix-PREROUTING (1 references)
     pkts bytes target     prot opt in     out     source               destination
        0     0 felix-FIP-DNAT  all  --  *      *       0.0.0.0/0            0.0.0.0/0
        0     0 DNAT       tcp  --  *      *       0.0.0.0/0            169.254.169.254      tcp dpt:80 to:127.0.0.1:8775
    [...]
