Vmnics Might Be Down After an Upgrade to ESXi 8.0

Products

• VMware vCenter Server 8.0

Issue/Introduction

After upgrading to ESXi 8.0, vmnics might remain down if the peer physical switch does not support auto negotiation or if the feature is disabled on the switch. If the vmnic link is set down and then brought up again, the link remains down after the upgrade or installation of ESXi 8.0.

Environment

VMware vSphere ESXi 8.0

Cause

This issue occurs when the peer physical switch does not support auto negotiation or when the feature is disabled on the switch. After upgrading to ESXi 8.0, the VMNIC link remains down if auto negotiation is not enabled or properly configured in the peer physical switch.

Resolution

To resolve this issue, you have these options:

Option 1: Enable Media Auto Detect in BIOS if the peer physical switch does not support auto negotiation

1. Access the host's BIOS settings by pressing F2 or opening a virtual console.
2. Navigate to the System Setup Main Menu.
3. Go to Device Settings and select the specific Broadcom NIC.
4. Enter the Device Configuration Menu.
5. Enable Media Auto Detect.
6. Reboot the host for the changes to take effect.

Option 2: Use an ESXCLI Command to Set a Fixed Speed in case the physical switch does not support auto negotiation

1. Use the following ESXCLI command to set the speed and duplex for the NIC

esxcli network nic set -S <your speed> -D full -n <your nic>

      2. This command sets a fixed speed to the link and does not require a reboot. It is also persistent across reboots.

Option 3: Enable Auto Negotiation on the physical peer switch

Additional Information

Reference: VMware vCenter Server 8.0 Update 3d Release Notes