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

Products

• VMware vCenter Server

Issue/Introduction

The upgrade of the vCenter Server Appliance fails during the pre-check phase. You may observe the following behaviors:

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

• Review of the 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
  
  

• Warnings such as:

  This ESXi host [//XXX.XXX.XX.XX:443] is managed by vCenter Server [XXX.XXX.XX.XX].

Environment

VMware vCenter Server 8.0.x

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 KB:

  • Troubleshooting vCenter Appliance /storage/log directory is 80% or more 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.