Unable to add hosts in SDDC Manager with Error : "Failed to configure vswitch to DVS vmknic migration on host"

Products

• VMware SDDC Manager

Issue/Introduction

While navigating to SDDC Manager > Cluster >Add hosts, it fails with below error :

 

The /var/log/vmware/vcf/domainmanager/ domainmanager.log indicates:

 ERROR [vcf_dm,69####################] 
[c.v.e.s.c.c.v.vsphere.VcManagerBase,dm-exec-18] 
Unable to migrate vmknic vmk0 -- retrying 1 
com.vmware.vim.binding.vmodl.fault.HostCommunication: 
An error occurred while communicating with the remote host.

Environment

VMware Cloud Foundation 5.x

Cause

A VLAN mismatch is identified between the management network on the vSphere Standard Switch (vSS) and the vSphere Distributed Switch (vDS). During the vmk0 migration, the host temporarily loses connectivity due to this mismatch, resulting in a HostCommunication error and failure of the migration task.

Resolution

To resolve the issue, it is recommended to Deploy new cluster and ensure that the management network VLAN configuration is correctly defined during cluster creation.

This approach ensures that:

• The management network is automatically created and managed by SDDC Manager.

• The correct VLAN configuration is applied from the beginning.

• The vmk0 migration from vSS to vDS can complete without network interruption.

Additional Information

The above  error indicates that host communication is interrupted while attempting to migrate the vmk0 interface from the standard switch to the distributed switch. Since vmk0 is the management interface of the host, any disruption in connectivity during migration can cause the task to fail

For successful vmk0 migration from vSS to vDS, the VLAN configuration on both source and destination port groups must match. If they differ, the host loses management connectivity during migration, causing SDDC Manager communication failure and a HostCommunication error, as confirmed by log analysis and network validation.