On 6/8/2017 10:17 AM, Arne Wiebalck wrote:
On 08 Jun 2017, at 15:58, Matt Riedemann <mriede...@gmail.com
<mailto:mriede...@gmail.com>> wrote:
Nova stores the output of the Cinder os-initialize_connection info API
in the Nova block_device_mappings table, and uses that later for
making volume connections.
This data can get out of whack or need to be refreshed, like if your
ceph server IP changes, or you need to recycle some secret uuid for
your ceph cluster.
I think the only ways to do this on the nova side today are via volume
detach/re-attach, reboot, migrations, etc - all of which, except live
migration, are disruptive to the running guest.
I've kicked around the idea of adding some sort of admin API interface
for refreshing the BDM.connection_info on-demand if needed by an
operator. Does anyone see value in this? Are operators doing stuff
like this already, but maybe via direct DB updates?
We could have something in the compute API which calls down to the
compute for an instance and has it refresh the connection_info from
Cinder and updates the BDM table in the nova DB. It could be an admin
action API, or part of the os-server-external-events API, like what we
have for the 'network-changed' event sent from Neutron which nova uses
to refresh the network info cache.
Other ideas or feedback here?
I have opened https://bugs.launchpad.net/cinder/+bug/1452641 for this
issue some time ago.
Back then I was more thinking of using an alias and not deal with IP
addresses directly. From
what I understand, this should work with Ceph. In any case, there is
still interest in a fix :-)
Cheers,
Arne
--
Arne Wiebalck
CERN IT
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Yeah this was also discussed in the dev mailing list over a year ago:
http://lists.openstack.org/pipermail/openstack-dev/2016-May/095170.html
At that time I was opposed to a REST API for a *user* doing this, but
I'm more open to an *admin* (by default) doing this. Also, if it were
initiated via the volume API then Cinder could call the Nova
os-server-external-events API which is admin-only by default and then
Nova can do a refresh.
Later in that thread Melanie Witt also has an idea about doing a refresh
in a periodic task on the compute service, like we do for refreshing the
instance network info cache with Neutron in a periodic task.
--
Thanks,
Matt
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