vCenter Server Appliance Upgrade Fails with “Internal error occurs during execution of upgrade process.” during Pre-checks

Products

• VMware vCenter Server

Issue/Introduction

Upgrade of vCenter Server Appliance fails during the pre-check phase. You may observe the following symptoms:

• UI displays the message:
  “Internal error occurs during execution of upgrade process.”

• Review of log file /var/log/vmware/upgrade/upgrade-requirements.log reveals messages similar to:

  [YYYY-MM-DDTHH:MM:SS] ERROR transport Command [...] exit-code=1, stdout=, stderr=Caught unhandled exception. Error: Traceback (most recent call last): ... File "os.py", line 241, in makedirs OSError: [Errno 28] No space left on device: '/var/log/vmware/upgrade'

• Additional log entries may include:

  [YYYY-MM-DDTHH:MM:SS] ERROR upgrade_commands Pre-upgrade checks failed. Check upgrade-source-requirements.log log for details. [YYYY-MM-DDTHH:MM:SS] ERROR upgrade_commands Unable to download pre-upgrade checks result file
   

Environment

VMware vCenter Server

Cause

The upgrade process attempts to write temporary files to the /var/log/vmware/upgrade directory. If the underlying partition (/storage/log) does not have sufficient free space, the pre-check script fails with a “No space left on device” (Errno 28) error. This causes the upgrade process to abort before completing the verification phase.

Resolution

To resolve the issue:

1. Free Up Disk Space in /storage/log

• Identify large or obsolete log files under /storage/log.

• Safely delete unnecessary files following the steps outlined in the VMware KBs:

  • vCenter log disk exhaustion or /storage/log full

  • vCenter Server Appliance disk space is full

2. (Optional) Expand the Disk

• If cleaning up files is not sufficient, consider expanding the virtual disk associated with /storage/log.

• After expansion, use the VAMI interface or CLI to resize the partition.

3. Retry the Upgrade

• Once sufficient space is available, reinitiate the upgrade process. The pre-checks should now pass without error.

Additional Information

Impact / Risks

• The upgrade cannot proceed until the disk space issue is resolved.
• Ensure that DRS automation mode is not set to Fully Automated on clusters during the upgrade process, as highlighted in upgrade warnings.

 

Related KBs:

vCenter Appliance Upgrade fails at Stage 2 (50%) with Error 'A problem occurred while - Exporting VMware vCenter Authentication Framework data..'

"The log partition size on this vCenter Server is smaller than the recommended 50 GB", increase the disk space of /storage/log to 50GB on vCenter 8.0