Adding an ESX or ESXi host to vCenter Server fails at 80% with error: Cannot install the vCenter agent - Unknown Installer Error

Products

• VMware vCenter Server

Issue/Introduction

Symptoms:

• Adding an ESX or ESXi host to vCenter Server fails at 80%
• You see the error:
  
  Cannot install vCenter Agent Service. Unknown Installer Error.
  
  
• The host's /var/log/vmware/hostd.log file contains an entry similar to:
  
  [2010-08-31 10:22:52.018 F62EBB90 warning 'Proxysvc Req00038'] Connection to named pipe /var/run/vmware/proxy-vpxa failed with error N7Vmacore15SystemExceptionE(No such file or directory).

Environment

VMware vCenter Server 4.0.x
VMware vCenter Server 4.1.x

Resolution

This issue can occur if the root partition of the host is full. To verify that the root partition is full, run the command: df -h

To resolve this issue free disk space on the root partition of the ESX host. For more information, see Investigating disk space on an ESX host (1003564).