vCenter Server Appliance Update Fails with Exception in postinstallHook for B2B-patching

Products

• VMware vCenter Server
• VMware vCenter Server 8.0

Issue/Introduction

When attempting to update the vCenter Server Appliance, the update fails with the following error message:
"Exception occurred in postinstallHook for B2B-patching. Please check the logs for more details. Take corrective action and then resume."

The following log entries may be present in the /var/log/vmware/applmgmt/PatchRunner.log file.

YYYY-MM-DDTHH:MM:SS.492Z wcp:Patch ERROR wcp Failed to patch WCP service
YYYY-MM-DDTHH:MM:SS.492Z wcp:Patch ERROR vmware_b2b.patching.executor.hook_executor Patch hook 'wcp:Patch' failed.
Traceback (most recent call last):
  File "/storage/updatemgr/software-update6zgksf2z/stage/scripts/patches/py/vmware_b2b/patching/executor/hook_executor.py", line 74, in executeHook
    executionResult = systemExtension(args)
  File "/storage/updatemgr/software-update6zgksf2z/stage/scripts/patches/libs/sdk/extensions.py", line 106, in __call__
    result = self.extension(*args)
  File "/storage/updatemgr/software-update6zgksf2z/stage/scripts/patches/libs/sdk/extensions.py", line 123, in _func
  return func(*args)
  File "/storage/updatemgr/software-update6zgksf2z/stage/scripts/patches/payload/components-script/wcp/__init__.py", line 211, in doPatching
    doIncrementalPatching(current_version)
  File "/storage/updatemgr/software-update6zgksf2z/stage/scripts/patches/payload/components-script/wcp/__init__.py", line 329, in doIncrementalPatching
    raise user_error
patch_errors.UserError: Failed to apply patch wcpsvc yaml config! Error: argument of type 'NoneType' is not iterable.

Additionally, reviewing the /etc/vmware/wcp/wcpsvc.yaml configuration file reveals truncated or incomplete entries, or the rhttpproxy_port value is unparsed and set as follows:
rhttpproxy_port: {rhttpproxy.ext.port2}

Environment

VMware vCenter Server 8.x

Cause

This issue occurs because the  /etc/vmware/wcp/wcpsvc.yaml configuration file is corrupted, truncated, or contains unparsed variables, which causes the WCP patching hook to fail during the vCenter Server Appliance update process.

Resolution

Note: Take an offline snapshot of the vCenter Server or create a backup of the wcpsvc.yaml file before making any changes.

1.Login to the vcenterserver using SSH as root user

2.Make a copy of the file
# cp /etc/vmware/wcp/wcpsvc.yaml /etc/vmware/wcp/wcpsvc.yaml.bak

3.Review the contents of the wcpsvc.yaml file. If the entries display the unparsed variable rhttpproxy_port: {rhttpproxy.ext.port2}, follow the remediation steps outlined in KB 326225 to resolve the issue.

• Alternatively, if the wcpsvc.yaml file is truncated or missing entries, Restore a valid wcpsvc.yaml file from a known good backup or from a healthy node running the exact same version.

Additional Information

WCP service fails to start in vCenter Server due to incorrect entry for the reverse HTTP proxy port in /etc/vmware/wcp/wcpsvc.yaml