vCenter patching failure: "Invalid Type, expected String, instead got NoneType"

Products

• VMware vCenter Server 8.0

Issue/Introduction

• vCenter server patching via VAMI fails with the error: "Pre-Install Failed for NetDumper.Expand".
  
  
• Reviewing /var/log/vmware/applmgmt/PatchRunner.log on the vCenter server:
  YYYY-MM-DD HH:MM:SSZ netdumper:Expand INFO netdumper Starting the expand hook for Netdumper Service.
YYYY-MM-DD HH:MM:SSZ netdumper:Expand INFO netdumper Backing up netdump core directory.
YYYY-MM-DD HH:MM:SSZ netdumper:Expand ERROR netdumper Expand script failed with error : [Errno 2] No such file or directory: '/var/core/netdumps' -> '/var/core/netdumps_backup'
YYYY-MM-DD HH:MM:SSZ netdumper:Expand ERROR vmware_b2b.patching.executor.hook_executor Patch hook 'netdumper:Expand' failed.
Traceback (most recent call last):
  File "/storage/seat/software-updateoix5gniw/stage/scripts/patches/py/vmware_b2b/patching/executor/hook_executor.py", line 74, in executeHook
    executionResult = systemExtension(args)
  File "/storage/seat/software-updateoix5gniw/stage/scripts/patches/libs/sdk/extensions.py", line 106, in __call__
    result = self.extension(*args)
  File "/storage/seat/software-updateoix5gniw/stage/scripts/patches/libs/sdk/extensions.py", line 123, in _func
    return func(*args)
  File "/storage/seat/software-updateoix5gniw/stage/scripts/patches/payload/components-script/netdumper/__init__.py", line 107, in expand
    os.rename(NETDUMPER_DIR, NETDUMPER_BACKUP_DIR)
FileNotFoundError: [Errno 2] No such file or directory: '/var/core/netdumps' -> '/var/core/netdumps_backup'
YYYY-MM-DD HH:MM:SSZ ERROR vmware_b2b.patching.utils.phase_utils Patch hook Expand got ComponentError.
...
...
... 
patch_errors.ComponentError 
YYYY-MM-DD HH:MM:SSZ WARNING root stopping status aggregation... 
YYYY-MM-DD HH:MM:SSZ ERROR __main__ Pre-patch vCSA failed.

Environment

vCenter Server 8.x

Cause

This is caused due to the missing netdumps and netdump_backup directories in the core partition (/var/core/).

Resolution

1. Create netdumps and netdump_backup directories under /var/core/ with the following ownership.
   cd /var/core
mkdir netdumps
mkdir netdumps_backup
chown netdumper:netdumper netdumps
chown netdumper:netdumper netdumps_backup
   
   
2. Assign required permissions to both the directories.
   chmod 700 netdumps
chmod 700 netdumps_backup
   
   
3. To resolve the failed update task in VAMI, follow the steps outlined in the below article.
   Resolving the "Update is not staged" Loop During VMware vCenter Patch or Update
   
   
4. Retry the vCenter Server patching process.