The Set CPU Count and Memory for VM action is used to add or remove CPUs and memory on virtual machines with only one power off of the virtual machines to perform the combined actions. You modify the CPU and memory to address performance problems or to reclaim resources.

How the Action Works

The Set CPU Count and Memory action powers off the target virtual machines. The action also creates a snapshot when requested and changes the number of vCPUs and memory based on the new CPU count and memory values you provided. As well, the action returns the virtual machines their original power states.

An alternative form of the Set CPU Count and Memory for Virtual Machine action is available for automation. This version of the action has the Power Off Allowed flag set to true so that the action is available for automation and can run when the virtual machine is in the powered on state. You can select the 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 activated 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.

To run the action, all options where you configure a value must contain a value for the objects that you want to change. If you are changing one option to a new value, but not another option, ensure that the option that you are not changing is configure with the current value.

Where You Run the Action

For the supported objects and object levels, this action is available in the following locations in VMware Aria Operations:
  • Embedded just below the top menu.
  • From the left menu click Environment > Object Browser, select an object, click the Details tab, and click Views.
  • From the left menu click Environment > Object Browser. Select an object, click the Environment tab, and select an object in the list view.
  • From the left menu click Environment and then click Inventory. Select an object in the list.
  • In configured alert recommendations.
  • In the Object List and Topology Graph dashboard widgets.

Action Options

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 activate the OK button.


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


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 activated, 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 suggested size. If the target virtual machine is new or offline, this value is the current number of CPUs. If VMware Aria Operations has been monitoring the virtual machine for six 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 section in VMware Aria Operations Configuration Guide. .


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 activated, then the snapshot is taken with the virtual machine is running, which consumes more disk space.


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

Adapter Instance Name of the VMware Adapter as it is configured in VMware Aria Operations. 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.

Table 1. Task ID Dialog Box
Option Description
OK To close the dialog box without further action, click OK.
Recent Tasks To view the status of the job and verify that the job finished, click Recent Tasks.