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[Florian Haas <florian@xxxxxxxxxxx>]

Hi everyone,

perhaps someone can shed some light on a floating IP issue.

I have 2 nova-compute nodes (call them alice and bob), one of them
(alice) is also running nova-network. bob uses alice as its
--metadata_host and --network_host.

I assign a floating IP to a guest running on bob. Expectedly, that IP
is bound to the NIC specified as the --public_interface on alice (my
nova-network host).

However, since alice has a route into the --fixed_range network over
its local bridge, the incoming traffic for the floating IP is routed
there, where there's no guest to answer it -- because the guest is,
after all, running on bob.

Now, this seems fairly logical to me in the combination of

1. a nova-network host also running nova-compute;
2. other nova-compute hosts being around;
3. those other nova-compute hosts _not_ also running nova-network (and
hence there being no multi-host networking).

If my reasoning is correct, is it safe to say that in order to be able
to use floating IPs in an environment with multiple nova-compute
hosts, you must

1. Either have a single nova-network host that is _not_ also running
nova-compute (but has a network connection to the --fixed_range
network, of course);
2. or run nova-network on all your nova-compute hosts, which however
requires that you enable multi-host mode and also run nova-api there?

Any help is much appreciated. Thanks!

Cheers,
Florian