[one-users] Some questions about overcommitment in OpenNebula 4.2 using KVM

[Gerry O'Brien]

Hi,

     Do you know if the CPU parameter has any effect on the amount of 
real cpu used, e.g. if I set the CPU parameter to 0.1 will this limit 
the actual cpu usage?

     Also, can the monitor driver be  configured to report multiples of 
memory and allow memory overcommitment in the same way?

         Gerry

On 15/10/2013 19:28, Shankhadeep Shome wrote:
> I just configure the monitor driver to report 2x the cpu than it normally
> does. Basically when the monitor picks up the amount of cpu, lets say 1600
> for a 16 core cpu, I configure the monitor to report 3200 or some other
> multiplier. I find scheduling with cgroups a bit hairy, I do use cpusets to
> jail vms to specific numa nodes and avoid cross memory domain traffic but
> that's about it.
>
>
> On Fri, Oct 11, 2013 at 10:20 AM, Gerry O'Brien <gerry at scss.tcd.ie> wrote:
>
>> Hi,
>>
>>      Is overcommitment in OpenNebula 4.2 using KVM possible? If so, how is
>> it done?
>>
>>      Am I correct in believing that by default cgroups are not enabled and
>> that the only use of the CPU parameter is to guide the scheduler? If
>> cgroups are not enabled and the CPU paramter is set very low, say 0.1, for
>> a VM then can the cpu share actually used by the VM can be much larger than
>> 0.1?
>>
>>      What is the correct interpretation of the "used CPU" value on the
>> Sunstone Virtual Machines view?
>>
>>      Can balloon drivers be used with KVM in OpenNebula? If so, is there
>> any way around the fact that the MEMORY parameter seems to stop the
>> allocation of VMs to a host once the total sum of all MEMORY parameters
>> exceeds the physical memory available on the host?
>>
>>      Is there any good reason why the scheduler only uses 90% of available
>> memory by default?
>>
>>      I've tried searching the documentation and threads but cannot find any
>> answers to these questions so any help would be much appreciated.
>>
>>          Regards,
>>              Gerry
>>
>> --
>> Gerry O'Brien
>>
>> Systems Manager
>> School of Computer Science and Statistics
>> Trinity College Dublin
>> Dublin 2
>> IRELAND
>>
>> 00 353 1 896 1341
>>
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>>


-- 
Gerry O'Brien

Systems Manager
School of Computer Science and Statistics
Trinity College Dublin
Dublin 2
IRELAND

00 353 1 896 1341