[Engine-devel] [oVirt 3.3 Localization Question #8] Cluster Policy Function Label "Weights Modules"

[Gilad Chaplik]

----- Original Message -----
> From: "Yuko Katabami" <ykatabam at redhat.com>
> To: engine-devel at ovirt.org
> Sent: Monday, August 5, 2013 9:52:18 AM
> Subject: [Engine-devel] [oVirt 3.3 Localization Question #8] Cluster Policy Function Label "Weights Modules"
> 
> Hello all,
> 
> I would like to ask another question:
> 
> File: ApplicationConstants
> Resource ID: clusterPolicyFunctionLabel
> String: Weights Modules
> Question: Could anyone please describe what this is referring to and where on
> the portal it appears?

Hi Yuko,
 
it appears at: Configure (system level entity) -> cluster policies.

I'm going to add descriptions (=blue info icons) next to each section with the following text:

Filter:
Filters represents hard constraints for running a VM.
Each filter implements logic which validates a minimum requirements in order to run a VM.
For example, minimum RAM, CPU, designated host, etc. Hosts who fail this validation
are filtered out from the current request.

Weight:
Weights represent soft constraints for running a VM.
Note: in a weighting system, lower score is considered better. So a host with the
lowest score (weight) is the one the scheduler will choose.
Each weight module scores any given host based on an optimization logic the module
implements. For example, if we want to optimize for CPU load, the module will score
each host based on its known CPU load.
Weight modules scores are being summed, so it is possible to have more than one
weight module. The way to prioritize modules is by increasing / decreasing a factor.

Balance:
Load balancing is a logic that determines which hosts are over-utilized and which
are under-utilized. Then, the balancing mechanism calls the scheduler trying to
migrate a VM from an over-utilized to an under-utilized host. 
Note that it is important to choose a balancing module that does not conflict with
the weight module. Such a policy may destabilize this cluster.
Only a single load-balancing module is supported.

Custom properties:
These properties are needed for one of the above modules, so they will appear when
needed. Setting it when creating a policy generates the default values, which may
be overridden in each specific cluster using this policy.

(high level feature description: http://wiki.ovirt.org/Features/oVirtScheduler).

Thanks, 
Gilad.

> 
> Thank you,
> 
> Yuko
> 
> --
> Regards,
> 
> Yuko Katabami (方波見裕子)
> Technical Translator II
> NAATI Accredited Professional Translator (English into Japanese) #28138
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> Mobile: +61 415 847 352
> Email: ykatabam at redhat.com
> 
> 
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