ESXi host disconnected from vCenter and missing vmnic adapters after reboot

Products

• VMware vSphere ESXi

Issue/Introduction

An ESXi host loses network connectivity and appears in a disconnected state in the vCenter Server inventory following a reboot. When reviewing the host, the following symptoms are observed:

• The management interface (vmk0) displays as "Void" under team-pnic, when validated via "esxtop" >> "n" command.
  
  

• Running the below commands on the ESXi SSH session do not return any output:

  • esxcfg-nics -l
  • esxcli network nic list

• The physical network interfaces (such as vmnic0 and vmnic1) are recognized as PCI devices but are entirely missing from the ESXi host's network inventory.

• The driver module (for example nmlx5_core) is successfully enabled and loaded.
  
  

Environment

VMware vSphere ESXi

Cause

• After upgrading the ESXi host or after replacing a new PCIe NIC adapter, the NICs are not recognized by the ESXi host indicating a failure in hardware device discovery.
• The physical NICs are not being enumerated on the PCIe bus, preventing the ESXi host from detecting the hardware.
• The issue can be due to:
  • Incompatible driver/firmware versions. 
  • Other hardware issues. Example: Faulty PCIe Slot.

Note: The network cards may be seen as healthy on the hardware side, however the commands above show that they are not being presented correctly to the ESXi host.

Resolution

Please follow below KB for resolution:
Network cards not detected on an ESXi host