Configuring ESXi host with NSX-T Data Center, vCenter may generate alarm "Lost Network Connectivity"

Products

• VMware NSX

Issue/Introduction

• When you configure an ESXI host with NSX-T you may see an alarm in vCenter about ESXI disconnected. 
• The vmnic showing alarm is not related with the NSX-T configuration.
• In ESXi log /var/run/log/vobd.log the following messages maybe seen :

[vob.net.pg.uplink.transition.down] Uplink: vmnicX is down. Affected portgroup: Management Network. 1 uplinks up. Failed criteria: 128[vob.net.pg.uplink.transition.down] Uplink: vmnicX is down. Affected portgroup: vMotion. 0 uplinks up. Failed criteria: 128

• Note: vmnics above are not specific to NSX-T configuration.

Environment

VMware NSX-T Data Center

Cause

When the ESXI host is prepared for NSX-T, the datapath init script causes the device driver to preform a detach and re-attach operation on the vmnics to re-associate uplinks on all portsets to make sure ENS driver can get a chance to attach the device.

Resolution

This is a momentary event at the ESXI host preparation and will automatically recover.

 

This issue is resolved in VMware NSX-T 3.2.1 available at Broadcom Downloads.
If you are having difficulty finding and downloading software, please review the Download Broadcom products and software KB.