[openstack-dev] [cinder] [nova] whether the ServiceGroup in Cinder is necessary

Michał Dulko michal.dulko at intel.com
Tue Dec 22 14:16:09 UTC 2015

On 12/22/2015 01:29 PM, Erlon Cruz wrote:
> Hi Li,
> Can you give a quick background on servicegroups (or links to. The
> spec you linked only describe the process on Nova to change from what
> they are using to tooz)? Also, what are the use cases and benefits of
> using this?
> Erlon

This is simply and idea to be able to use something more sophisticated
than DB heartbeats to monitor services states. With Tooz implemented for
that we would be able to use for example ZooKeeper to know about service
failure in a matter of seconds instead of around a minute. This would
shrink the window in which c-sch doesn't-know-yet that c-vol failed and
sends RPC messages to a service that will never answer. I think there
are more use cases related to service monitoring and failover.

Service groups isn't probably a correct name for proposed enhancement -
we have this concept somehow implemented, but proposed idea seems to be
related to making it pluggable.

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