[Openstack] Multiple nova-compute hosts, single-host nova-network, and a guest unreachable via its floating IP
Florian Haas
florian at hastexo.com
Tue Jun 19 17:52:04 UTC 2012
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
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