vCloud Allocation Models, vCenter Resource Pools, and Per VM Resource Settings, Say What?

Allocation Pool Model

So now let’s look at the third option in detail known as the Allocation Pool model.  This is similar to the Reservation Pool whereas the settings are applied to the vCenter Resource Pool itself.  The difference is the users cannot control the vApp resources only the system administrator can alter those from vCloud Director.

Allocation Pool Allocation Settings

Now again in vCenter here is what the Resource Pool shows which is very much the same as the Reservation Pool settings.  The main difference is we not only set the allocations, but we can set a percentage guarantee on this vDC so that not all the resources are pre-allocated.  Based on the percentages the actual amounts will vary on the reservations and limits.  We also note that like the Reservation Pool there is NO expandable reservation or anything unlimited.

Allocation Pool Model vCenter Resource Pool

This means only the system administrator can alter the settings of the vDC and all the Virtual Machines within it will in turn look similar to that of the Reservation Pool, but users cannot edit or control them as we see below.  What we also see is the per VM settings are a hybrid of the previous two models.  The CPU is wide open but the memory gets set to limits and reservations to preserve the memory settings.  This is where we see that this model is more of a hybrid of the other two where we set the resource pool and the virtual machine.  Frankly this appears to be possibly something incorrect as there is no vCD option to change or set the per VM resource information.  I am looking into this further because on the surface it just does not look right to me.

UPDATE: I did look further into the settings for a Virtual Machine under the Allocation Pool Model, and by design the percentage settings on the pool are ALSO passed down to the indivudual VM which is why the memory reservation is set.  However, it seems ONLY the memory is set as indicated below NOT the CPU reservation.  This explains why each virtual machine has settings specific to them inside the Allocation Pool Model.  However, in the UI the only mention of the settings is that they are applied to the Resource Pool, but as I said the percentages are also applied to each Virtual Machine.

CPU Limits Assigned per VM in Allocation Pool Model
Memory Limits Assigned per VM in Allocation Pool Model

About Chris Colotti

Chris is active on the VMUG and event speaking circuit and is available for many events if you want to reach out and ask. Previously to this he spent close to a decade working for VMware as a Principal Architect. Previous to his nine plus years at VMware, Chris was a System Administrator that evolved his career into a data center architect. Chris spends a lot of time mentoring co-workers and friends on the benefits of personal growth and professional development. Chris is also amongst the first VMware Certified Design Experts (VCDX#37), and author of multiple white papers. In his spare time he helps his wife Julie run her promotional products as the accountant, book keeper, and IT Support. Chris also believes in both a healthy body and healthy mind, and has become heavily involved with fitness as a Diamond Team Beachbody Coach using P90X and other Beachbody Programs. Although Technology is his day job, Chris is passionate about fitness after losing 60 pounds himself in the last few years.

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