Service hosts and virtual machines in the VMM compute fabric


This version of Virtual Machine Manager (VMM) has reached the end of support. We recommend you to upgrade to VMM 2022.

Read this article to learn about service Hyper-V hosts and virtual machines in the System Center Virtual Machine Manager (VMM) fabric.

Before you start

We recommend you keep hosts in a Hyper-V host cluster up-to-date with the same updates to avoid VMM operations issues.

You can service hosts and VMs by:

  • Setting up servicing windows: Servicing windows provide a method for scheduling servicing outside VMM. You can associate a servicing window with individual hosts, virtual machines, or services. Before using other applications to schedule maintenance tasks, you can use Windows PowerShell scripts or custom applications to query the object and determine if it's currently in a servicing window. Servicing windows don't interfere with the regular use and functionality of VMM.
  • Placing hosts in maintenance mode: You can start the maintenance mode for a virtual machine host whenever you need to perform maintenance tasks on the physical host, such as applying security updates or replacing hardware on the physical host computer. You can place Hyper-V hosts and VMware ESX hosts in the VMM fabric into maintenance mode.


  • When a host is in maintenance mode, the following restrictions apply:
    • VMs can't be created on the host.
    • VMs can't be moved to the host.
    • The host has a zero rating and can't be selected for placement.
    • The host is excluded from dynamic optimization.
  • For ESX hosts, if the VMware Distributed Resources Scheduler is not configured, all virtual machines on the host must be either manually shut down or moved to another host to successfully start maintenance mode on an ESX host.
  • If you're monitoring with the Operations Manager and you've maintenance mode enabled for monitoring, the Operations Manager agent suppresses alerts, notifications, rules, monitors, automatic responses, state changes, and new alerts for hosts that are placed in maintenance mode.

Set up a servicing window

  1. In the VMM console, select Settings > Create > Create Servicing Window.
  2. In New Servicing Window, specify a name and optional description for the window.
  3. In Category, enter or select the category of servicing window.
  4. In Start time, enter the date, time of day, and time zone for the maintenance window.
  5. In Duration, specify the number of hours or minutes in the servicing window.
  6. Under Recurrence pattern, select the frequency (Daily, Weekly, or Monthly), and then schedule the occurrences within that frequency.
  7. After the window is set up, you can assign it to a host or VM. To assign to a host, select the host properties > Servicing Window > Manage, and select the window you want to add to the host.

Put hosts in maintenance mode

  1. In the VMM console, select Fabric > Fabric Resources > Servers > All Hosts.
  2. Select the host to place in maintenance mode, and in the Host group, select Start Maintenance Mode.
    • You can select Move all virtual machines to other hosts in the cluster if you want to move all highly available VMs to other hosts in the cluster (the host must be in a cluster that's capable of live migration).
    • Otherwise, select Place all running virtual machines into a saved state. Note that list causes a loss of service for users currently using the VM.
  3. You can verify that the host is in maintenance mode by checking its status in Fabric > Hosts.

To bring a host out of maintenance node, select it and select Stop Maintenance Mode.


VMM doesn't automatically restart the VM, and doesn't automatically migrate VMs back to the host.