Unable to place vSAN node into maintenance mode

Products

• VMware vSAN

Issue/Introduction

Symptoms:

• Unable to place the host into maintenance mode.
  
  
• Unable to migrate VMs on recently upgraded ESXi host. 
  
  

Validations:

• On the skyline health we found below alerts -
  
  
  
• Objects are in reduced state. Select "Troubleshoot" on the "vSAN object health" skyline health alert.
  
  
  
• Sync issue between host's maintenance mode and decommission state. Select "Troubleshoot" on the "Host Maintenance Mode" skyline health alert.
  

Environment

VMware vSphere ESXi 7.x

VMware vSphere ESXi 8.x

Cause

• vSAN host is in vSAN decommission state, it doesn't accept any new object creation, and all components on the host will be absent until it is back. 
  
  
• When the host in the vSAN cluster is in maintenance mode, it is expected that this host is in vSAN decommission state. When the host exits maintenance mode, the host should not be in vSAN decommission state. "Host Maintenance Mode" health check verifies the two states are in sync. If a host is in maintenance mode using any of the vSAN options but is not in vSAN decommission state, or a host exits maintenance mode but is still in vSAN decommission state, the check triggers a warning message under skyline health.
  
  
  
  From command line, the state of the host will still show up as in maintenance mode.
  [root@ESXi1 :~ ] esxcli vsan cluster get
Cluster Information
Enabled: true
Current Local Time: 2025-04-21T07:49:50Z
Local Node UUID: 63cf7e3f-####-####-####-84160ca67a20
Local Node Type: NORMAL
Local Node State: BACKUP
Local Node Health State: HEALTHY
Sub-Cluster Master UUID: 63cf9dcf-####-####-####-00620b621de0
Sub-Cluster Backup UUID: 63cf7e3f-####-####-####-84160ca67a20
Sub-Cluster UUID: 521b5900-####-####-####-4aa8f4d678a5
Sub-Cluster Membership Entry Revision: 146
Sub-Cluster Member Count: 3
Sub-Cluster Member UUIDs: 63cf9dcf-####-####-####-00620b621de0, 63bed45e-####-####-####-00505692e5fa, 63cf7e3f-####-####-####-84160ca67
Sub-Cluster Member HostNames: ESXi1, ESXi2, ESXi3
Sub-Cluster Membership UUID: 98dd0468-####-####-####-00620b621de0
Unicast Mode Enabled: true
Maintenance Mode State: ON
Config Generation: c61cb566-####-####-####-f5e7bf5f24f5 5 2025-04-20T20:59:17.780
Mode: REGULAR
VSAN ESA Enabled: false

Resolution

• Run data migration precheck and if it succeeds without any indication of inaccessible object after the host entering into maintenance mode, only then we can proceed with adding the host into maintenance mode.
  
  
  Run the below command to perform the precheck using CLI -
  

  [root@ESXi1 :~ ] esxcli vsan debug evacuation precheck -e localhost
Action: No Action
Evacuation Outcome: Success
Entity: Host localhost
Data to Move: 0.00 GB
Number of Objects That Would Become Inaccessible: 0
Objects That Would Become Inaccessible: None
Number of Objects That Would Have Redundancy Reduced: 0
Objects That Would Have Redundancy Reduced: None
Additional Space Needed for Evacuation: N/A

  Action: Ensure Accessibility
Evacuation Outcome: Success
Entity: Host localhost
Data to Move: 0.00 GB
Number of Objects That Would Become Inaccessible: 0
Objects That Would Become Inaccessible: None
Number of objects That Would Have Redundancy Reduced: 0
Objects That Would Have Redundancy Reduced: None
Additional Space Needed for Evacuation: N/A

  Action: Evacuate All Data
Evacuation Outcome: Success
Entity: Host localhost
Data to Move: 0.00 GB
Number of Objects That Would Become Inaccessible: 0
Objects That Would Become Inaccessible: None
Number of Objects That Would Have Redundancy Reduced: 0
Objects That Would Have Redundancy Reduced: None
Additional Space Needed for Evacuation: N/A

• Place the host into maintenance mode.
  
  
• Exit out of maintenance mode.

Additional Information

vSAN Health Service - Data Health – vSAN Object Health

vSAN Health Service - Performance Service - Stats DB object check

vSAN Host Maintenance Mode is in sync with vSAN Node Decommission State