Hi Florian, For my own setup, I wanted to achieve highly-available network, and avoid the loss of the gateway of every instances running if nova-network falls down. I couldn't afford 2 dedicated nodes to put nova-network itself in an highly available state. Now if I loose a nova-network on a compute node, all my instances running on this compute node will loose their gateway but this scenario is better than loosing all my VMs. The multi_host was the best option and I think it's applicable to every setup. So precisely, every compute node hosts those services:
- nova-compute - nova-network - avoid networking SPOF - nova-api-metadata - you don't need the entire nova-api service. Each new instance only needs to reach the metadata. Running this from the compute node can also improve performance with the cloud-init service. Of course this setup works with the multi_host parameter enable. My 2 cts contribution ;) On Tue, Jun 19, 2012 at 7:52 PM, Florian Haas <flor...@hastexo.com> wrote: > 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 > > _______________________________________________ > Mailing list: https://launchpad.net/~openstack > Post to : openstack@lists.launchpad.net > Unsubscribe : https://launchpad.net/~openstack > More help : https://help.launchpad.net/ListHelp
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