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On 05/08/2015 12:41 AM, Arne Wiebalck wrote:
> Hi Josh,
>
> In our case adding the monitor hostnames (alias) would have made only a
> slight difference:
> as we moved the servers to another cluster, the client received an
> authorisation failure rather
> than a connection failure and did not try to fail over to the next IP in
> the list. So, adding the
> alias to list would have improved the chances to hit a good monitor, but
> it would not have
> eliminated the problem.

Could you provide more details on the procedure you followed to move
between clusters? I missed the separate clusters part initially, and
thought you were simply replacing the monitor nodes.

> I’m not sure storing IPs in the nova database is a good idea in gerenal.
> Replacing (not adding)
> these by the hostnames is probably better. Another approach may be to
> generate this part of
> connection_info (and hence the XML) dynamically from the local ceph.conf
> when the connection
> is created. I think a mechanism like this is for instance used to select
> a free port for the vnc
> console when the instance is started.

Yes, with different clusters only using the hostnames is definitely
the way to go. I agree that keeping the information in nova's db may
not be the best idea. It is handy to allow nova to use different
clusters from cinder, so I'd prefer not generating the connection info
locally. The qos_specs are also part of connection_info, and if changed
they would have a similar problem of not applying the new value to
existing instances, even after reboot. Maybe nova should simply refresh
the connection info each time it uses a volume.

Josh