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
[...]