How to create an Elastic vDC in VMware vCloud director
Something that was slipped into vCloud 1.5 that did not get much press was the idea on an elastic vDC. This gives the ability to add extra capacity to the underlying provider vDC in vCloud. If you have worked with vCloud before you might be saying wait I could always do this by expanding the size of my cluster or pool that was providing the resources. And this was certainly one option for adding more capacity. But what if you had larger clusters that could not be expanded or if you were using linked clones (Fast Provisioning) and you reached the 8 host maximum for your cluster. You would have to create a new provider vDC and present this capacity as a new Org vDC to your cloud consumer.
The idea of an elastic vDC allows you to add another resource pool to a provider vDC which in turn presents this capacity up to the Org vDC. Now today this option is only available for Org vDCs that are setup for the Pay as You Go allocation model. What it allows you to do is add in the resources from additional vCenter resource pools to a provider vDC. Thus allowing you to grow the resources that are presented up to any Org vDCs using the proper allocation model.
You can see from the image at the bottom of this post that the first resource pool presented is marked as the primary and is what would be used to provide resources to Org vDCs that are using the Allocated or Reserved allocation models.
To add another resource pool you must navigate to the provider vDC that you wish to add the resources to and select the resource pool tab. Then simple click the green plus icon to add the resources by selecting from the vCenter that you choose. Below is a summary of the VMware KB that describes the features and limitations as they stand today.
One of the key defining characteristics of a cloud is elasticity, which means that the container through which a tenant consumes resources can grow and shrink. In vCloud Director 1.5, Pay-As-You-Go organization vDCs are made elastic. Now, multiple resource pools can be added to a single provider vDC and capacity from all of these resource pools can be made available to a single Pay-As-You-Go organization vDC.This elasticity is restricted to:
- Only the Pay-As-You-Go organization vDCs. The Reservation Pool and Allocation Pool vDC are still bound to a single provider vDC resource pool.
- A single vCenter Server Datacenter (provider vDC resource pools cannot span multiple vCenter Server Datacenters)
The system administrator is allowed to add/remove multiple resource pools to/from an existing Provider vDC, thus making it possible for a Provider vDC to be backed by multiple resource pools. When the provider vDC is created, user selects a primary resource pool. Allocation Pool and Reservation Pool organization vDCs consume resources from this primary resource pool. After creating the provider vDC, additional resource pools can be added to the provider vDC, so that Pay-As-You-Go organization vDCs using that provider vDC can expand, as required, to accommodate more virtual machines.
Found the above info in VMware KB