Procedure to remove and re-add a vSAN Node to the Cluster Following OS Reinstallation

Products

• VMware vSAN

Issue/Introduction

This KB article outlines the procedure to safely remove and re-add a vSAN node to a cluster in scenarios where hardware failures require the reinstallation of the ESXi operating system. Following the documented steps ensures that the vSAN cluster remains stable and data integrity is preserved during the host removal and reintegration process.

Environment

VMware VSAN 7.x

VMware VSAN 8.x

Resolution

Following the correct procedure is crucial when removing and re-adding a vSAN Node to the Cluster

• Ensure that there is no resync running on the vSAN cluster before starting the activity.
  

• Ensure there is sufficient capacity in the vSAN disk groups to remove a node.

• Ensure the number of remaining nodes in the vSAN cluster post removing a node is compliant with the current storage policy. If not change the current storage policy to be compliant with the remaining nodes in the vSAN cluster.

• Right click on the host which is to be removed > Maintenance mode > Enter Maintenance mode > Pre-check.
  

  This pre-check simulates what the cluster would look like if it is not contributing to the vSAN cluster. From the pre-check results:

  Verify that none of the vSAN objects go in reduced availability or inaccessible state.

  Verify that there is enough space in the cluster.

  Once verified that all is green, put the host into maintenance mode with full data migration selected. This will evacuate all disk groups on the host.

  Wait for resync traffic to complete and the host to enter maintenance mode.

• For vSAN OSA after the host is in maintenance mode delete the disk group(s) that reside on the host you want to remove:

       Select the vSAN cluster > Configure > Disk Management > Select the host to be decommissioned > View Disks > Select the disk group >Remove the Disk group
  

  For vSAN ESA remove the disks that reside on the host you want to decommission:

       Select the vSAN cluster > Configure > Disk Management > Select the host to be decommissioned > View Disks > Select the disks > Remove Disk

• Move the ESXi host out of the cluster to disassociate it from vSAN

• Reinstall the OS on the ESXi host.

• Once the OS is reinstalled, drag and drop the ESXi host back to the VSAN cluster.

• Exit the host from maintenance mode

• Run the command esxcli vsan cluster get and validate if the host is part of the VSAN cluster

• Select the vSAN cluster > Configure > Disk Management > Select the host > View Disks > Create Disk group