"Network uplink redundancy lost" alarm triggered for vmnic0 going down

Products

• VMware vSphere ESXi

Issue/Introduction

This resolution article is regarding the vSphere alarm "Network uplink redundancy lost" triggering for a host's vmnic0 going down.

Commonly, the vmnic0 is configured for Management Network traffic. This makes this alarm potentially severe, if triggered. This article serves to aid in reviewing potential causes for this alarm triggering.

Environment

vCenter Server 7.x

vSphere ESXi 7.x

Resolution

1) For the host that triggered this alarm, click the host in vCenter Server inventory, followed by the Monitor tab, and then the Tasks row.

2) Expand the alarm and view the Description. It should contain "Lost uplink redundancy on virtual switch vSwitch0. Physical NIC vmnic0 is down. Affected portgroups:...".

3) Note the Date of the alarm trigger.

4) SSH into the host as the root user.

5) Using the noted date time of the triggered alarm, refer to the steps in knowledge article "Network adapter (vmnic) is down or fails with a Failed Criteria Code" to get more information about the vmnic0 going down.

Additional Information

 

Network cards not detected on an ESXi host

https://knowledge.broadcom.com/external/article?articleNumber=324505