[ovirt-users] Power Management - but no LO?

[Daniel Helgenberger]

Hello Eli,

thanks for getting back to me. Sadly the matter does not seem quite 
clear for me right now; at least I have to read deeper into fence agents.

On 19.11.2014 10:26, Eli Mesika wrote:
>
>
> ----- Original Message -----
>> From: "Daniel Helgenberger" <daniel.helgenberger at m-box.de>
>> To: users at ovirt.org
>> Sent: Tuesday, November 18, 2014 5:46:07 PM
>> Subject: [ovirt-users] Power Management - but no LO?
>>
>> Hello,
>>
>> I am toying an idea involving using oVirt's PM capabilities (esp. the
>> cluster power_saving policy) in conjuration with some consumer grate
>> hosts for raw compute applications.
>>
>> Now, these hosts do not have any lights out or BMC capabilities.
>> However, they could be started with WOL packets.
>>
>> Is there a way how this can be done in oVirt? Shutting down hosts with
>> ssh and starting them with WOL?
>
> Yes, but you will have to write your own custom fencing script for that and configure it as explain in
> http://www.ovirt.org/Custom_Fencing (look in the oVirt 3.5 section)
Is there any more documentation available? I found some older docs [1], 
are they still valid?
I struggle with how the mapping is done from parameters in the PM tab to 
functions in my fence agent, how it is passed to it and how it gets 
called in the end.
As I understood so far, oVirt needs to proxy PM/fencing operations and 
is using one host of the cluster for fencing; and PM the appropriate 
device. Also, I can use engine-config register the fence agent as well 
as to map some generic fields.

>
> If you need any details, please ask but mainly you should look on the scripts in the fence-agents package (/usr/sbin/fence_*) and write something that supports the common flags used by those scripts
Some basic design concepts I thought of so far:
I assume the virsh fence agent could work for me. It ssh's to the host. 
I would call shutdown in this case I think?
Further, while compiling the appropriate WOL packet seems trivial in 
python, I need to map an NIC MAC address witch I could get from a 
parameter in the PM setup. But in this case, any host could be used 
execute the script; preferring the engine in this case? Or is this a bad 
approach for some reason? (Assuming the NIC is part of ovirt management 
net).

I think I can manage to do this once I have figured out the basic stuff. 
Strangely, though I found posts by people who also tried to attempt a 
WOL fence agent this as not been accomplished it seems. Can you think of 
a reason? (I can think of shutdown, witch needs ssh to be done).

Thanks for any help on the issue.

[1] http://www.ovirt.org/Features/HostPMProxyPreferences
>
>
>>
>> Thanks!
>>
>> --
>> Daniel Helgenberger
>> m box bewegtbild GmbH
>>
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>>
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>>
>>
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>

-- 
Daniel Helgenberger
m box bewegtbild GmbH

P: +49/30/2408781-22
F: +49/30/2408781-10

ACKERSTR. 19
D-10115 BERLIN


www.m-box.de  www.monkeymen.tv

Geschäftsführer: Martin Retschitzegger / Michaela Göllner
Handeslregister: Amtsgericht Charlottenburg / HRB 112767