3.1 vCloud Director Multitenancy
In providing a multitenancy overlay, vCloud Director introduces some new terms for the constructs that describe that multitenancy model. The terms, which are used throughout the rest of this document are described briefly in the following table. For a more detailed explanation, see the documents linked in the Section
7,
References.
Table 1. VMware vCloud Director Tenancy Terms
Term | Description |
Organization | An organization is a logical group of all users to whom resources will be presented. |
Provider virtual data center | A provider VDC is a collection of vSphere resources (storage, CPU and memory) that vCloud Director can manage and use. |
Organization virtual data center | An Organization VDC is a subset of a Provider VDC’s resources that are available to an Organization. |
The following figures illustrate these concepts.
Figure 7. Service Provider Data Center vSphere Clusters and Resource Pools
In
Figure 7, the data center has two vCenter Server nodes, each managing two clusters. Under vCenter-01, the two clusters contain different types of hosts. Cluster-01 has hosts with higher CPU clock speeds for CPU intensive workloads, where Cluster-02 has hosts with extra memory allowing for hosts with higher memory demands. vCenter-02 on the other hand, contains two clusters with the same type of hosts, each with a balance of clock speed and memory designed for general workloads. Because it is not possible to place a resource pool anywhere other than across all hosts in a cluster, and vCloud Director places workloads within a resource pool, all hosts in a single resource pool, and therefore cluster, should be of the same type to ensure consistent performance.
Because a Provider VDC (PVDC) is connected to a single vCenter Server, the vCloud Director example in
Figure 7 must have at least two vCenter Server nodes. However, to allow for the placement of workloads on either high CPU or high memory hosts, the resources under vCenter-01 should be split into two Provider VDCs, each mapped to a resource pool in one of the clusters. Because a Provider VDC can have multiple resource pools from the vCenter Server assigned to it, vCenter-02’s resources could be presented as two separate Provider VDCs or, as shown in
Figure 8, one PVDC with multiple resource pools.
Figure 8. Mapping Provider VDCs to vSphere Resources
The PVDC presents resources that can be consumed by the Organizations who subscribe to the Provider’s Cloud service. To present the resources to those Organizations, vCloud Director uses an Organization VDC (Org VDC or simply OVDC) to represent a subset of a Provider VDC. A customer, represented by a vCloud Director Organization can access multiple Organization VDCs. In the example illustrated in
Figure 8, a customer might require some high memory workloads and some standard ones, in which case they have two OVDCs, one in PVDC2 and one in PVDC3. A customer who only requires standard workloads might have a single OVDC, or might choose to have two to enforce different oversubscription ratios or workload placements for production and development workloads.
When accessing vCloud Director, an Organization’s users with appropriate access privileges see all of their OVDCs listed.
