ESXi is down due to uplink associated with management kernel missing

Products

• VMware vSphere ESXi

Issue/Introduction

• ESXi host is down/disconnected in vCenter
• Running esxtop command shows that the management vmk (in this case vmk0) doesn't have any vmnic associated and shows void as in below screenshot
  
  
  
  
• DVS inspection revealed that there is no uplink attached to the DVS containing management kernel.
  
  

 

Environment

• VMware vCenter Server 7.x
• VMware vCenter Server 8.x

Cause

As for any network connectivity, it is crucial for the management VMkernel to have an uplink associated with it. Since in this case there was no uplink attached to the DVS/Management vmk, host lost network connectivity

 

Resolution

• Check the management kernel state using esxtop command and confirm it has a valid uplink associated with it and required vLANs are allowed on the uplink 
• Add/assign the correct uplink back to the DVS port via CLI: Using the following commands on the vDS:
  
  esxcfg-vswitch -Q vmnicX -V dvPort_ID_of_vmnic "dvSwitch" # Remove/unlink a vDS uplink
esxcfg-vswitch -P vmnicX -V unused_dvPort_ID "dvSwitch" # Add/link a vDS uplink

Note : If the issue persist after attaching a valid uplink, please open a case with Broadcom support team. 

 

 

Additional Information

For more troubleshooting steps, refer:  Troubleshooting an ESXi host in a "not responding"/"disconnected" state