<font size=2 face="sans-serif">There are roughly three cases.</font>
<br><font size=2 face="sans-serif">1. Multiple identical instances of the
scheduler service. This is typically done to increase scalability, and
is already supported (although sometimes may result in provisioning failures
due to race conditions between scheduler instances). There is a single
queue of provisioning requests, all the scheduler instances are subscribed,
and each request will be processed by one of the instances (randomly, more
or less). I think this is not the option that you referred to, though.</font>
<br><font size=2 face="sans-serif">2. Multiple cells, each having its own
scheduler. This is also supported, but is applicable only if you decide
to use cells (e.g., in large-scale geo-distributed deployments).</font>
<br><font size=2 face="sans-serif">3. Multiple scheduler configurations
within a single (potentially heterogeneous) Nova deployment, with dynamic
selection of configuration/policy at run time (for simplicity let's assume
just one scheduler service/runtime). This capability is under development
(</font><a href=https://review.openstack.org/#/c/37407/><font size=3 color=blue><u>https://review.openstack.org/#/c/37407/</u></font></a><font size=3>)
</font><font size=2 face="sans-serif">, targeting Havana. The current design
is that the admin will be able to override scheduler properties (such as
driver, filters, etc) using flavor extra specs. In some cases you would
want to combine this capability with a mechanism that would ensure disjoint
partitioning of the managed compute nodes between the drivers. This can
be currently achieved by using host aggregates and AggregateInstanceExtraSpec
filter of FilterScheduler. For example, if you want to apply driver_A on
hosts in aggregate_X, and dirver_B on hosts in aggregate_Y, you would have
flavor AX specifying driver_A and properties that would map to aggregate_X,
and similarly for BY.</font>
<br>
<br><font size=2 face="sans-serif">Hope this helps.</font>
<br><font size=2 face="sans-serif"><br>
Regards,</font>
<br><font size=2 face="sans-serif">Alex</font>
<br>
<br>
<br>
<br><font size=1 color=#5f5f5f face="sans-serif">From:
</font><font size=1 face="sans-serif">sudheesh sk <sudh03@yahoo.com></font>
<br><font size=1 color=#5f5f5f face="sans-serif">To:
</font><font size=1 face="sans-serif">"openstack-dev@lists.openstack.org"
<openstack-dev@lists.openstack.org>, </font>
<br><font size=1 color=#5f5f5f face="sans-serif">Date:
</font><font size=1 face="sans-serif">13/08/2013 10:30 AM</font>
<br><font size=1 color=#5f5f5f face="sans-serif">Subject:
</font><font size=1 face="sans-serif">[openstack-dev]
Can we use two nova schedulers at the same time?</font>
<br>
<hr noshade>
<br>
<br>
<br><font size=3 face="Roman">Hi,</font>
<br>
<br><font size=3 face="Roman">1) Can nova have more than one scheduler
at a time? Standard Scheduler + one custom scheduler?</font>
<br>
<br><font size=3 face="Roman">2) If its possible to add multiple schedulers
- how we should configure it. lets say I have a scheduler called 'Scheduler'
. So nova conf may look like below scheduler_manager = nova.scheduler.filters.SchedulerManager
scheduler_driver = nova.scheduler.filter.Scheduler Then how can I add a
second scheduler</font>
<br>
<br><font size=3 face="Roman">3) If there are 2 schedulers - will both
of these called when creating a VM?</font>
<br>
<br>
<br><font size=3 face="Roman">I am asking these questions based on a response
I got from ask openstack forum</font>
<br>
<br><font size=3 face="Roman">Thanks,</font>
<br><font size=3 face="Roman">Sudheesh</font><tt><font size=2>_______________________________________________<br>
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