vCenter Shows Host Status is Unknown During NSX Prep with vLCM

Products

• VMware NSX
• VMware vSphere ESXi
• VMware vCenter Server

Issue/Introduction

When preparing hosts or a cluster for NSX in a vLCM-enabled environment, vCenter Server may report the host status as "Unknown." This condition blocks image compliance checks and suspends the NSX installation on the affected hosts.

The issue is triggered by a failure to connect to the depot URL, as shown in the following error message:

Failed to connect to depot: 'URL: 'http://<vCenter FQDN>:9084/vum/repository/hostupdate/__micro-depot__vendor-vmw__vmw-ESXi-<version>-metadata__index__.xml' 
Error: '<urlopen error [Errno -2] Name or service not known>'

 

 

 

Environment

VMware NSX

VMware vSphere ESXi

VMware vCenter Server

Cause

This issue occurs when ESXi hosts are unable to resolve the vCenter Server's Fully Qualified Domain Name (FQDN). As a result, the hosts cannot establish a connection to the depot URL required for image compliance and NSX installation tasks.

Resolution

To confirm the DNS resolution issue, run the nslookup command directly on the affected ESXi host against the vCenter FQDN. If the lookup fails, it indicates that the configured DNS server cannot resolve the name.

To resolve the issue, update the ESXi host to use a DNS server capable of resolving the vCenter FQDN. For detailed instructions, refer to KB 328870.