The vCenter API call to Power ON VM fails stright after reconfiguring the VM.

Products

• VMware vCenter Server

Issue/Introduction

The VM (Virtual Machine) Power On operation is attempted immediately following the VM reconfiguration.

• The following error messages are observed:
  

  vCenter Task Error: The available memory resources in the parent resource pool are insufficient for the operation.

• The subsequent Power ON request completes successfully.

Environment

VMware vCenter 8.x

Cause

The product works as per the design.
The VM configuration is updated every 60 seconds for optimization and improve performance.

Resolution

Workaround:

Method 1: Manual Delay
After reconfiguring the VM memory via the API, wait at least 1 minute before attempting to power on the virtual machine. This allows the background configuration refresh to complete.

Method 2: Adjust Advanced DRS Options
If you require immediate power-on capabilities without a delay, you can disable the specific optimization that causes the 60-second lag:

1. Navigate to the ESXi Cluster in the vSphere Client.
2. Go to the Configure tab.
3. Select vSphere DRS and then click Advanced Options.
4. Add the following property:
   Option: NewDeltaAlloc
   Value: 1
5. Click OK.