Testing the Monitoring Virtual Machines functionality in vCenter Server


Monitoring virtual machines is a supported function in VMware VirtualCenter 2.5 Update 2 and later.
This article provides the procedure used to test the functionality of the Monitoring Virtual Machines process in VirtualCenter.


The Monitoring Virtual Machines component is a function of the VMware High Availability (HA) tool in VMware VirtualCenter. This feature is discussed in depth in the Availability Guide . Ensure you have reviewed this information prior to proceeding with this test.

Environment Configuration

To configure your environment to use Monitoring Virtual Machines:
  1. Configure VMware HA on the cluster. For more information, see the Creating and Using VMware HA Clusters section of the Availability Guide  for your product version .
  2. Enable Monitoring Virtual Machines feature, and define a sensitivity setting. For more information, see the Turning On Fault Tolerance for Virtual Machines section of the Availability Guide  for your product version.
  3. Install VMware Tools on the virtual machine being used for testing. For more information, see the Installing and Upgrading VMware Tools section of the  Installing and Configuring VMware Tools.
  4. Verify VM Restart Priority for the virtual machine does not have Disabled selected. For more information, see the Selecting HA Options section of the Resource Management Guide .

Test Procedure

The following test simulates a loss of heartbeat signal from the virtual machine to replicate a monitoring failure. To create this loss of signal, you need to terminate the VMware Tools processes within the guest. When the heartbeat signal is lost, VMware HA monitors the signal for a predefined failure interval. After this failure interval has elapsed, VMware HA attempts to restart the virtual machine. For ESX hosts with hostd logging set to verbose, information is logged to the /var/log/vmware/hostd log files.  
Note: vCenter Server 4.0 introduces an additional disk I/0 status check after the virtual machine heartbeat fails to prevent accidental reboots. This check ensures to wait for 120 seconds of no disk I/O operation before the restart happens. Because of this check, you could follow the steps above and still not witness a restart of the virtual machine. To prevent this, disable the disk I/O check by using the das.iostatsInterval advanced HA attribute. For more information on the das.iostatsInterval HA attribute, see the Customizing VMware HA Behavior section of the Availability Guide  for your product version.
To disable the heartbeat, follow the procedure for the type of guest operating system installed on the virtual machine:

Windows Guest

You can stop the VMware Tools Heartbeat signal by stopping the VMware Tools service and VMwareUser.exe process within Windows.

Note: In vCenter Server 5.0, the 
VMwareUser.exe process is replaced by vmtoolsd.exe .

Linux Guest

Run the following command to disable VMware Tools:

/etc/init.d/vmware-tools stop