Unexpected error while upgrading NSX host – RPC timed out while running command DownloadLcp on host

Products

• VMware NSX

Issue/Introduction

On the NSX UI -> System -> Upgrade -> Hosts , NSX upgrade on the Host tab is stuck with the error :

"Unexpected error while upgrading upgrade unit:
RPC timed out while running command DownloadLcp on host
(<hostname>, <UUID>)".

 

Environment

VMware NSX

Cause

This happens due to RPC time out while running command IsHostInMaintenanceMode on host.

This issue occurs when the NSX Manager is unable to maintain a stable RPC connection with the ESXi host during the DownloadLcp stage of the host upgrade.
The communication timeout can occur due to:

• Temporary interruption in NSX Manager-to-host communication.

• Unresponsive or stalled NSX services (e.g., nsx-proxy, opsagent, nsstdp) on the host.

• Heavy resource utilization or latency during the upgrade process.

Resolution

1. Restart NSX services on the affected host:

/etc/init.d/nsx-proxy restart
/etc/init.d/opsagent restart

2. Retry the host upgrade.

If the upgrade fails again, proceed to restart the following services on the NSX Manager:/etc/init.d/proton restart

#/etc/init.d/upgrade-coordinator restart

3. Retry the upgrade again after the above service restarts.