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.

Floating IPs - 图1note

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:

  1. Create tenant network and subnet.

    1. neutron net-create --shared calico
    2. neutron subnet-create --gateway 10.65.0.1 --enable-dhcp --ip-version 4 --name calico-v4 calico 10.65.0.0/24

  2. Boot a VM on that network.

    1. nova boot [...]

  3. Find its Neutron port ID.

    1. neutron port-list

  4. Create an external network and subnet; this is where floating IPs will be allocated from.

    1. neutron net-create public --router:external True
    2. neutron subnet-create public 172.16.1.0/24

  5. Create a router connecting the tenant and external networks.

    1. neutron router-create router1
    2. neutron router-interface-add router1 <tenant-subnet-id>
    3. neutron router-gateway-set router1 public

  6. Create a floating IP and associate it with the target VM.

    1. neutron floatingip-create public
    2. 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.

  7. From a compute node, issue the following command.

    1. ip r

    It should return the routing table.

    1. default via 10.240.0.1 dev eth0
    2. 10.65.0.13 dev tap9a7e0868-da  scope link
    3. 10.65.0.14 via 192.168.8.4 dev l2tpeth8-3  proto bird
    4. 10.65.0.23 via 192.168.8.4 dev l2tpeth8-3  proto bird
    5. 10.240.0.1 dev eth0  scope link
    6. 172.16.1.3 dev tap9a7e0868-da  scope link
    7. 192.168.8.0/24 dev l2tpeth8-3  proto kernel  scope link  src 192.168.8.3
    8. 192.168.122.0/24 dev virbr0  proto kernel  scope link  src 192.168.122.1

  8. Issue the following command to review iptables.

    1. sudo iptables -L -n -v -t nat

    It should return something like the following.

    1. [...]
    2. Chain felix-FIP-DNAT (2 references)
    3.  pkts bytes target     prot opt in     out     source               destination
    4.     0     0 DNAT       all  --  *      *       0.0.0.0/0            172.16.1.3           to:10.65.0.13
    6. Chain felix-FIP-SNAT (1 references)
    7.  pkts bytes target     prot opt in     out     source               destination
    8.     0     0 SNAT       all  --  *      *       10.65.0.13           10.65.0.13           to:172.16.1.3
    10. Chain felix-OUTPUT (1 references)
    11.  pkts bytes target     prot opt in     out     source               destination
    12.     1    60 felix-FIP-DNAT  all  --  *      *       0.0.0.0/0            0.0.0.0/0
    14. Chain felix-POSTROUTING (1 references)
    15.  pkts bytes target     prot opt in     out     source               destination
    16.     1    60 felix-FIP-SNAT  all  --  *      *       0.0.0.0/0            0.0.0.0/0
    18. Chain felix-PREROUTING (1 references)
    19.  pkts bytes target     prot opt in     out     source               destination
    20.     0     0 felix-FIP-DNAT  all  --  *      *       0.0.0.0/0            0.0.0.0/0
    21.     0     0 DNAT       tcp  --  *      *       0.0.0.0/0            169.254.169.254      tcp dpt:80 to:127.0.0.1:8775
    22. [...]