In NSX 6.2.0 VMware adds the ability to create communication channel health. The channel health status between
- NSX Manager and the firewall agent: A heartbeat is sent every 3 minutes, if two iterations are lost a sync will occur.
- NSX Manager and the control plane agent: A heartbeat is sent every 2 minutes, if two iterations are lost a sync will occur.
- Host and the NSX Controller: Heartbeats are sent every 30 seconds, if three iterations are lost a sync will occur.
The channel health status can be seen from the NSX Manager UI. In addition, this feature detects when configuration messages from the NSX Manager have been lost before being applied to a host, and it instructs the host to reload its NSX configuration when such message failures occur.
The following diagram shows the communication channels involved in the communication:
All the host / cluster that have been prepared for NSX runs VSFWD (Firewall Agent) & NETCPA (Network Control Plane agent). To verify the Communication Channel Health log into the vSphere Web Client and navigate to Networking & Security plugin -> Installation –> Host Preparation. Select the Cluster/Individual host and click on Actions and then Communications Channel Health.
In case hosts looses the connectivity with NSX controllers then you will see the Control Plane Agent to Controller being down.
ESXi Host uses the NETCPA agent to communicate with the controllers, If there are issues with the NETCPA or VSFWD (firewall) agent then you will see an unknown error.
You can change the default interval that the host will send heartbeats by editing netcpa.xml located at following location on ESX Host.
This concludes how we can leverage channel health to verify if communication is working properly between different components. I hope this is informative for you. Thanks for reading !!!. Be social and share it in social media, if you feel worth sharing it.