The Set CPU action in vRealize Operations Manager modifies the number of vCPUs on a virtual machine. You increase the number of CPUs to address performance problems or decrease the number of CPU to reclaim resources.

The Set CPU Count action shuts down or powers off the target virtual machines, which is required if you are decreasing the CPU count. This action creates a snapshot if you request it, changes the number of vCPUs based on the new CPU count you provided, and returns the virtual machines to their original power states.

An alternative form of the Set CPU Count for Virtual Machine action is available for automation. This action can run when the virtual machine is powered on or off.

Use this version of the action if the automated action has permission to power off the virtual machine, and hot add of memory is not enabled on the virtual machine. With hot add enabled, you can add CPUs, but you cannot remove them.

This version of the action would be required if a virtual machine is powered on and the number of CPUs must be reduced.

This version of the action has the Power Off Allowed flag set to true. You can select this Power Off Allowed version of the action when you create or edit alerts and associate the alert with a recommendation. When the Power Off Allowed version of this action is automated, you do not select this version of the action.

If Hot Plug is enabled on the virtual machines, then power off is not required. If power off is required and VMware Tools are installed, then the virtual machines are shut down before they are powered off.

For the supported objects and object levels, this action is available in the following locations in vRealize Operations Manager:

In the Actions menu on the top toolbar when you click Home.

On the toolbar when you click Environment, select an object, click the Details tab, click Views, and select a view of type List.

On the toolbar when you click Environment, select an object, click the Environment tab, and select an object in the list view.

In the Inventory Explorer list when you click Administration, click Inventory Explorer, click the List tab, and select an object in the list.

In configured alert recommendations.

In the Object List and Topology Graph dashboard widgets.

Review the following information about the virtual machines to ensure that you are submitting the action for the correct objects.

Option

Description

Selected objects

Check box indicates whether the action is applied to the object. To not run the action on one or more objects, deselect the associated check boxes. This option is available when two or more objects are selected.

If you modify a value, the check box is selected. The check box must be selected to enable the OK button.

Name

Name of the virtual machine as it appears in the environment inventory.

New CPU

Number of CPUs when the action is completed. If the value is less than 1 or a value not supported for the virtual machine in vCenter Server, and the virtual machine is powered on and Hot Add is not enabled, the number of CPUs does not change and Recent Tasks shows the action as failed. If the virtual machine is powered off when you submit an unsupported value, the task reports success, but the virtual machine will fail when you run a power on action.

The value that appears is the calculated recommended size. If the target virtual machine is new or offline, this value is the current number of CPUs. If vRealize Operations Manager has been monitoring the virtual machine for 6 or more hours, depending on your environment, the value that appears is the CPU Recommended Size metric.

Current CPU

Number of configured CPUs.

Power State

Indicates whether the virtual machine is powered on or powered off.

Power Off Allowed

If selected, the action shuts down or powers off the virtual machine before modifying the value. If VMware Tools is installed and running, the virtual machine is shut down. If VMware Tools is not installed or not running, the virtual machine is powered off without regard for the state of the operating system.

In addition to whether the action shuts down or powers off a virtual machine, you must consider whether the object is powered on and what settings are applied.

See Working With Actions That Use Power Off Allowed.

Snapshot

Creates a snapshot before changing the number of CPUs. Use this option if you need a snapshot to which you can revert the virtual machine if the action does not produce the expected results.

The name of the snapshot is supplied in the Recent Tasks messages for the action.

If the CPU is changed with CPU Hot Plug enabled, then the snapshot is taken with the virtual machine is running, which consumes more disk space.

Host

Name of the host on which the virtual machine is running.

Adapter Instance

Name of the VMware Adapter as it is configured in vRealize Operations Manager. The adapter manages the communication with the vCenter Server instance.

After you click OK, the next dialog box provides the task ID and a link to the task list.

Task ID Dialog Box

Option

Description

Recent Tasks

To view the status of the job and verify that the job finished, click Recent Tasks.

OK

To close the dialog box without further action, click OK.