ESXi host updates might require that the host enters maintenance mode before the updates are applied. Update Manager puts ESXi hosts in maintenance mode before applying these updates. You can configure how Update Manager responds if the host fails to enter maintenance mode.

You cannot use vMotion to migrate virtual machines that run on individual hosts or on hosts that are not in a cluster. If vCenter Server cannot migrate the virtual machines to another host, you can configure how Update Manager responds.

Hosts that are in a vSAN cluster can enter maintenance mode only one at a time. This is a peculiarity of the vSAN cluster.

If a host is a member of a vSAN cluster, and any virtual machine on the host uses a VM storage policy with a setting for "Number of failures to tolerate=0", the host might experience unusual delays when entering maintenance mode. The delay occurs because vSAN has to migrate the virtual machine data from one disk to another in the vSAN datastore cluster. Delays might take up to hours. You can work around this by setting the "Number of failures to tolerate=1" for the VM storage policy, which results in creating two copies of the virtual machine files in the vSAN datastore.

The settings that you can configure in the vSphere Client and the vSphere Web Client. The following host and cluster remediation settings are not available in the vSphere Client:

  • Disable Distributed Power Management (DPM)
  • Disable High Availability Admission Control
  • Disable Fault Tolerance (FT)


Required privileges: VMware vSphere Update Manager.Configure


  1. In the vSphere Client, select Menu > Update Manager.
  2. Navigate to Menu > Update Manager.
  3. Click the Settings tab.
  4. Select Remediation Settings > Hosts.
  5. Click the Edit button.
    The Edit Settings for Host Remediation dialog box opens.
  6. Select an option from the drop-down menu to determine the change of the power state of the virtual machines that run on the host to be remediated.
    Option Description
    Power Off virtual machines Powers off all virtual machines before remediation.
    Suspend virtual machines Suspends all running virtual machines before remediation.
    Do Not Change VM Power State Leaves virtual machines in their current power state. This is the default setting.
  7. (Optional) Select the Retry entering maintenance mode in case of failure check box, and specify the retry delay, and the number of retries.
    If a host fails to enter maintenance mode before remediation, Update Manager waits for the retry delay period and retries putting the host into maintenance mode as many times as you indicate in the Number of retries text box.
  8. (Optional) Select Allow installation of additional software on PXE booted ESXi hosts check box.
    Selecting this option enables installation of software for solutions on PXE booted ESXi hosts in the vSphere inventory that you manage with this Update Manager instance.
  9. (Optional) Select the Migrate powered off and suspended virtual machines to other hosts in the cluster, if a host must enter maintenance mode check box.
    Update Manager migrates the suspended and powered off virtual machines from hosts that must enter maintenance mode to other hosts in the cluster. You can select to power off or suspend virtual machines before remediation in the Maintenance Mode Settings pane.
  10. (Optional) Select the Disconnect removable media devices that might prevent a host from entering maintenance mode check box.
    Update Manager does not remediate hosts on which virtual machines have connected CD/DVD or floppy drives. All removable media drives that are connected to the virtual machines on a host might prevent the host from entering maintenance mode and interrupt remediation.
  11. (Optional) Select the Enable Quick Boot check box.
    Update Manager significantly reduces the host reboot time during remediation. For Quick Boot compatibility, see KB 52477.
  12. Click Save.


These settings become the default failure response settings. You can specify different settings when you configure individual remediation tasks.