A reservation is a share of one compute resource's available memory, CPU and storage reserved for use by a particular fabric group. Each reservation is for one fabric group only but the relationship is many-to-many. A fabric group might have multiple reservations on one compute resource, or reservations on multiple compute resources, or both.

While reservations provide a method to allocate a portion of the cluster memory or storage within vRealize Automation, reservations do not control how CPU and memory is allocated during periods of contention on the underlying vSphere compute resources. vSphere Resource Pools are utilized to control the allocation of CPU and memory during time of resource contention on the underlying host. To fully utilize this, all VMs must be deployed into one of three resource pools: SDDC-EdgeRP01, User-EdgeRP01, and User-VMRP01. Core-NSX is dedicated for datacenter level NSX Edge components and should not contain any user workloads. User-EdgeRP01 is dedicated for any statically or dynamically deployed NSX components such as NSX Edges or Load Balancers which serve a specific customer workloads. User-VMRP01 is dedicated for any statically or dynamically deployed virtual machines such as Windows, Linux, databases, etc, which contain specific customer workloads.

Reservation Design Decisions

Decision ID

Design Decision

Design Justification

Design Implication

SDDC-CMP-038

Create at least one vRealize Automation reservation for each business group at each region.

In our example, each resource cluster will have two reservations, one for production and one for development, allowing both production and development workloads to be provisioned.

Because production and development share the same compute resources, the development business group must be limited to a fixed amount of resources.

SDDC-CMP-039

Create at least one vRealize Automation reservation for edge resources in each region.

An edge reservation in each region allows NSX to create edge services gateways on demand and place them on the edge cluster.

The workload reservation must define the edge reservation in the network settings.

SDDC-CMP-040

Configure all vRealize Automation workloads to utilize dedicated vCenter Resource Pools.

In order to ensure dedicated compute resources of NSX networking components, end-user deployed workloads must be assigned to a dedicated end-user workload vCenter Resource Pools. Workloads provisioned at the root resource pool level will receive more resources then resource pools, which would starve those virtual machines in contention situations.

Cloud administrators must ensure all workload reservations are configured with the appropriate resource pool. This may be a single resource pool for both production and development workloads, or two resource pools, one dedicated for the Development Business Group and one dedicated for the Production Business Group.

SDDC-CMP-041

Configure vRealize Automation reservations for dynamically provisioned NSX Edge components (routed gateway) to utilize dedicated vCenter Resource Pools.

In order to ensure dedicated compute resources of NSX networking components, end-user deployed NSX edge components must be assigned to a dedicated end-user network component vCenter Resource Pool. Workloads provisioned at the root resource pool level will receive more resources then resource pools, which would starve those virtual machines in contention situations.

Cloud administrators must ensure all workload reservations are configured with the appropriate resource pool.

SDDC-CMP-042

All vCenter resource pools utilized for Edge or Compute workloads must be created at the "root" level. Nesting of resource pools is not recommended.

Nesting of resource pools can create administratively complex resource calculations that may result in unintended under or over allocation of resources during contention situations.

All resource pools must be created at the root resource pool level.