VMs won't vMotion off Host when host is put into maintenance mode: vCenter Server

Products

• VMware vSphere ESXi
• VMware vCenter Server

Issue/Introduction

When attempting to place an ESXi host into Maintenance Mode or performing a vMotion, the task stalls between 29% and 32%, and fails to evacuate the host. This issue occurs within the vCenter Server Management component and affects VMware vSphere ESXi hosts during lifecycle management or manual maintenance operations.

• Maintenance mode task hangs indefinitely between 29% and 32%.
• vMotion operations do not initiate for running virtual machines.
• Warning messages may appear stating the host is waiting for VMs to be powered off or migrated.

Cause

The Distributed Resource Scheduler (DRS) automation level is set to Manual or Partially Automated.

• In this configuration, vCenter Server generates migration recommendations but will not automatically execute them.
• When a host is placed in maintenance mode, the system waits for the administrator to manually approve or initiate the migration of all virtual machines (including vCLS agent VMs) off the host.
• If no manual migration occurs, the task remains stalled at the 29% mark.

This issue will also occur if DRS is disabled/off.

Resolution

To resolve this issue, ensure that DRS is configured to automatically evacuate the host.

1. 1. Log in to the vSphere Client.
   2. Navigate to the Inventory and select the affected Cluster.
   3. Click the Configure tab.
   4. Under Services, select vSphere DRS and click Edit.
   5. Change the Automation Level to Fully Automated.
   6. Click OK.
   7. The maintenance mode task should now proceed as DRS automatically migrates the VMs to other hosts in the cluster.

NOTE: Alternatively, if Manual mode must be maintained:

1. 1. Identify all VMs currently running on the host <esxi_hostname>.
   2. Right-click each VM and select Migrate.
   3. Follow the wizard to move the VMs to another host in the cluster.
   4. Once the host is empty, the maintenance mode task will complete.