<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt">I have one quick question regarding the 3rd point you have mentioned (<font face="sans-serif" size="2">Multiple scheduler configurations
within a single (potentially heterogeneous) Nova deployment</font>)<br><br>In this case ultimately when a VM is created - would it have gone through all the schedulers or just one scheduler which was dynamically selected?<br>Is there any chance of having 2 schedulers impacting creation of one VM?<br><br><br>Thanks,<br>Sudheesh<div style="font-family: times new roman, new york, times, serif; font-size: 12pt;"> <div style="font-family: times new roman, new york, times, serif; font-size: 12pt;"> <div dir="ltr"> <hr size="1"> <font face="Arial" size="2"> <b><span style="font-weight:bold;">From:</span></b> Alex Glikson <GLIKSON@il.ibm.com><br> <b><span style="font-weight: bold;">To:</span></b> sudheesh sk <sudh03@yahoo.com>; OpenStack Development Mailing List <openstack-dev@lists.openstack.org> <br> <b><span style="font-weight: bold;">Sent:</span></b> Tuesday, 13 August 2013 1:45 PM<br> <b><span style="font-weight:
bold;">Subject:</span></b> Re: [openstack-dev] Can we use two nova schedulers at the same time?<br> </font> </div> <div class="y_msg_container"><br><div id="yiv7500383905"><font face="sans-serif" size="2">There are roughly three cases.</font>
<br><font face="sans-serif" size="2">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 face="sans-serif" size="2">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 face="sans-serif" size="2">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 rel="nofollow" target="_blank" href="https://review.openstack.org/#/c/37407"><font color="blue" size="3"><u>https://review.openstack.org/#/c/37407/</u></font></a><font size="3">)
</font><font face="sans-serif" size="2">, 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 face="sans-serif" size="2">Hope this helps.</font>
<br><font face="sans-serif" size="2"><br>
Regards,</font>
<br><font face="sans-serif" size="2">Alex</font>
<br>
<br>
<br>
<br><font color="#5f5f5f" face="sans-serif" size="1">From:
</font><font face="sans-serif" size="1">sudheesh sk <sudh03@yahoo.com></font>
<br><font color="#5f5f5f" face="sans-serif" size="1">To:
</font><font face="sans-serif" size="1">"openstack-dev@lists.openstack.org"
<openstack-dev@lists.openstack.org>, </font>
<br><font color="#5f5f5f" face="sans-serif" size="1">Date:
</font><font face="sans-serif" size="1">13/08/2013 10:30 AM</font>
<br><font color="#5f5f5f" face="sans-serif" size="1">Subject:
</font><font face="sans-serif" size="1">[openstack-dev]
Can we use two nova schedulers at the same time?</font>
<br>
<hr noshade="">
<br>
<br>
<br><font face="Roman" size="3">Hi,</font>
<br>
<br><font face="Roman" size="3">1) Can nova have more than one scheduler
at a time? Standard Scheduler + one custom scheduler?</font>
<br>
<br><font face="Roman" size="3">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 face="Roman" size="3">3) If there are 2 schedulers - will both
of these called when creating a VM?</font>
<br>
<br>
<br><font face="Roman" size="3">I am asking these questions based on a response
I got from ask openstack forum</font>
<br>
<br><font face="Roman" size="3">Thanks,</font>
<br><font face="Roman" size="3">Sudheesh</font><tt><font size="2">_______________________________________________<br>
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