Communication Alarms on the NSX UI while rebooting an ESXi that has NSX configuration

Products

• VMware NSX

Issue/Introduction

When an ESXi host is being restarted and the host has NSX configuration, there are NSX alarms that will show on the NSX manager UI.

Here are the following alarms that are common:

• Control Channel To Transport Node Down
• Management Channel To Transport Node Down
• Control Channel To Transport Node Down Long

Cause

Heart beating between NSX management node and host is down due a scheduled restart.

Resolution

These alarms are expected behavior when an ESXi host is being restarted. 

• vCenter Maintenance Mode: These alarms are normal when an ESXi host is rebooted, even while in maintenance mode in vCenter. They will automatically clear once the host is back online and reachable.
• NSX Maintenance Mode: The host into maintenance mode in both vCenter and NSX. In this scenario, the Control Channel To Transport Node Down Long alarm will be triggered. Just like the standard reboot, it resolved itself as soon as the host came back online and heart beats between the host and the NSX manager node. 

Additional Information

• Management Channel To Transport Node Down or Management Channel To Transport Node Down Long alarm is reported in NSX Manager
• "Control Channel To Transport Node Down Long" or "Management Channel to Transport Node Down Long" alarms for removed Transport Nodes