<font size=2 face="sans-serif">Thanks, I understand the Nova scheduler
part. One of the gaps there is related to the blueprint we have are working
on [1]. I was wondering regarding the role of Ironic, and the exact interaction
between the user, Nova and Ironic.</font>
<br><font size=2 face="sans-serif">In particular, initially I thought that
Ironic is going to have its own scheduler, resolving some of the issues
and complexity within Nova (which could focus on VM management, maybe even
getting rid of hosts versus nodes, etc). But it seems that Ironic aims
to stay at the level of virt driver API.. It is a bit unclear to me what
is the desired architecture going forward - e.g., if the idea is to standardize
virt driver APIs but keep the scheduling centralized, maybe we should take
the rest of virt drivers into separate projects as well, and extend Nova
to schedule beyond just compute (if it is already doing so for virt + bare-metal).
Alternatively, each of them could have its own scheduler (like the approach
we took when splitting out cinder, for example) - and then someone on top
(e.g., Heat) would need to do the cross-project logic. Taking different
architectural approaches in different cases confuses me a bit.</font>
<br>
<br><font size=2 face="sans-serif">Thanks,</font>
<br><font size=2 face="sans-serif">Alex</font>
<br>
<br><font size=2 face="sans-serif">[1] </font><a href="https://blueprints.launchpad.net/nova/+spec/multiple-scheduler-drivers"><font size=3 color=blue><u>https://blueprints.launchpad.net/nova/+spec/multiple-scheduler-drivers</u></font></a><font size=3>
</font>
<br><font size=2 face="sans-serif"><br>
</font>
<br>
<br>
<br>
<br><font size=1 color=#5f5f5f face="sans-serif">From:
</font><font size=1 face="sans-serif">Devananda van der Veen
<devananda.vdv@gmail.com></font>
<br><font size=1 color=#5f5f5f face="sans-serif">To:
</font><font size=1 face="sans-serif">"OpenStack Development
Mailing List (not for usage questions)" <openstack-dev@lists.openstack.org>,
</font>
<br><font size=1 color=#5f5f5f face="sans-serif">Date:
</font><font size=1 face="sans-serif">13/11/2013 10:29 PM</font>
<br><font size=1 color=#5f5f5f face="sans-serif">Subject:
</font><font size=1 face="sans-serif">Re: [openstack-dev]
[Nova] [Ironic] [TripleO] scheduling flow with Ironic?</font>
<br>
<hr noshade>
<br>
<br>
<br><font size=3>On Wed, Nov 13, 2013 at 8:02 AM, Alex Glikson <</font><a href=mailto:GLIKSON@il.ibm.com target=_blank><font size=3 color=blue><u>GLIKSON@il.ibm.com</u></font></a><font size=3>>
wrote:</font>
<br><font size=3 face="sans-serif">Hi, </font><font size=3><br>
</font><font size=3 face="sans-serif"><br>
Is there a documentation somewhere on the scheduling flow with Ironic?
</font><font size=3><br>
</font>
<br><font size=3 face="sans-serif">The reason I am asking is because we
would like to get virtualized and bare-metal workloads running in the same
cloud (ideally with the ability to repurpose physical machines between
bare-metal workloads and virtualized workloads), and would like to better
understand where the gaps are (and potentially help bridging them). </font>
<br>
<br><font size=3>Hi Alex,</font>
<br>
<br><font size=3>Baremetal uses an alternative scheduler, nova.scheduler.baremetal_host_manager.BaremetalHostManager,
so giving that a read may be helpful. It searches the available list
of baremetal nodes for one that matches the CPU, RAM, and disk capacity
of the requested flavor, and compares the node's extra_specs:cpu_arch to
that of the requested image, then consumes 100% of that node's available
resources. Otherwise, I believe the scheduling flow is basically the same:
http request to n-api, rpc passes to n-scheduler, which selects a node,
and calls to n-conductor & n-cpu to do the work of spawn()ing it.</font>
<br>
<br><font size=3>As far as the gaps in running both baremetal and virtual
-- I have been told by several folks that it's possible to run both baremetal
and virtual hypervisors in the same cloud by using separate regions, or
separate host-aggregates, for the simple reason that these require distinct
nova-scheduler processes. A single scheduler, today, can't serve both.
I haven't seen any docs on how to do this, though.</font>
<br>
<br><font size=3>As for moving a workload between them, the TripleO team
has discussed this and, afaik, decided to hold off working on it for now.
It would be better for them to fill in the details here -- my memory may
be wrong, or things may have changed.</font>
<br>
<br><font size=3>Cheers,</font>
<br><font size=3>Devananda</font>
<br>
<br>
<br>
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