[INFO] The Right vCloud Allocation Model For Catalogs • Chris Colotti's Blog

[INFO] The Right vCloud Allocation Model For Catalogs

I wanted to supply a small, yet interesting piece of information that Frank Denneman and I discovered while writing our upcoming white paper.  I want to preface the fact we are looking at this from the PROVIDER’s perspective.  So from a catalog storage aspect this would be the “Published” catalogs maintained by the provider.

In the course of examining the vCloud Allocation Models and their deeper relationship with vSphere, we did discover a helpful tip on your catalog vApps.  Essentially you want to create a Pay As You Go Org vDC to house all these catalog items.  The reason is simple without going into too much gory detail.  I will save that for the white paper.

The nature of the The Pay As You Go vCloud Allocation model is to assign resource settings to the individual virtual machines.  The resource pool itself has no settings assigned for limits and reservations.  This means that the virtual machines will not consume the reservations assigned unless they are powered on.  Since you cannot directly power on virtual machines and vApps in the catalog without deploying them, they will never consume any reservations while sitting in the catalog.  They will consume storage, but their per VM settings will not be factored in by vSphere for resource allocation.  The other two models, Reservation Pool and Allocation Pool, will assign reservations on the pool levels removing those resources from the provider vDC immediately.  If your intent is to only use this vDC for published catalogs, you would essentially be removing resources from your provider vDC for no reason.

This makes the Pay As You Go the perfect vCloud Allocation model for provider published catalogs.  Of course if you deploy these vApps, you will then be using the assigned reservations on the virtual machines, but you can of course deploy them to a different org vDC if you choose.  If you want to be really safe also be sure to set the Org vDC hosting these catalogs to 0% reservations.  This way if you DO deploy them to the same Org vDC, there will only be the overhead reservation required to power them on.

You may want to take this into account as a design consideration when you are designing your Organization and vDC’s.  Of course this does not apply to the consumer catalogs in an organization as they may only have access to their org vDC.  The catalog virtual machines for them will also be powered off and not affect their available resources.  The idea here is to make sure the Provider is not consuming Provider vDC resources by using an Allocation Pool or Reservation Pool model for unused virtual machines since those will allocate the reserved memory for the resource pool.

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  1. Only from a “Provider” perspective. For an Org, tenant of the cloud, it shouldn’t make a difference at all.

  2. Great Stuff Chris.  Keep up the good work

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