Resolving Severe vCenter Server Accessibility issues

Products

• VMware vCenter Server

Issue/Introduction

In the presence of severe ESXi storage or network communication issues, users may experience persistent login errors when attempting to access vCenter Server. Standard troubleshooting methods like certificate resets may fail to resolve the issue.

Environment

- vCenter Server 6.5 or similar versions
- ESXi hosts version 6.5 or comparable

Cause

Severe corruption of the vCenter Server database or critical system files due to ESXi host issues can lead to persistent authentication errors and system instability. This corruption may extend beyond simple certificate issues and can affect core vCenter functionality.

Resolution

1. Initial Troubleshooting:
   a. Attempt to resolve the issue using existing knowledgebase articles relevant to the specific symptoms.
   b. If standard troubleshooting fails, proceed to backup assessment.

2. Backup Assessment:
   a. Verify if you have a recent, valid backup of your vCenter Server.
   b. For vCenter 6.7 and newer, check if file-based backup is configured and operational.
   c. If multiple backups exist, identify the most recent successful backup.

3. Backup Restoration (if available):
   a. Power off the current vCenter VM.
   b. Restore the backup to a new VM with a different name.
   c. Power on the restored VM and verify functionality.
   d. If the restored VM resolves the issue, migrate your environment to this instance.
   e. If issues persist, try restoring an older backup following the same process.

4. Low-Level Diagnostics (if no valid backup):
   a. Restart the vCenter VM and carefully observe the startup console.
   b. Look for messages indicating corrupt files, bad sectors, or other data issues.
   c. If you encounter a "Failed to start file system check on /dev/disk..." error, follow the steps in "Failed to start file system check on /dev/disk..." error on Photon OS based virtual appliances

5. Check ESXi Host Health:
   a. Identify the ESXi host currently managing the vCenter VM.
   b. Review the host's logs for any hardware or storage-related errors:
      - Check /var/log/vmkernel.log for system-level issues.
      - Examine /var/log/hostd.log for host agent-related problems.
   c. Verify the host's storage connectivity and performance:
      - Run 'esxcli storage core path list' to check storage path status.
      - Use 'esxtop' to monitor storage latency and other performance metrics.
   d. Ensure all host services are running correctly:
      - Use 'services.sh status' to check service status.
   e. If any host issues are identified, address these before proceeding with vCenter troubleshooting.
   f. Consider migrating the vCenter VM to a known healthy host if possible.

Note: VMware support will likely perform similar host health checks as part of their diagnostic process. Proactively checking host health can provide valuable insights and potentially identify the root cause more quickly.

6. Engage VMware Support:
   a. If steps 1-4 do not resolve the issue, contact VMware support for assistance.
   b. Provide detailed information about your environment and the troubleshooting steps already taken.

7. vCenter Re-deployment (if recommended by VMware support):
   a. Assess your vCenter's complexity:
      - Count the number of ESXi hosts and VMs managed.
      - Note any virtual distributed switches in use.
      - Identify network link aggregation groups.
      - List any VMware add-on software (e.g., vSAN, NSX, vCloud Director).
      - Document customizations (SSO users, permissions, VM folders).
   b. Based on the complexity assessment, estimate the time required for re-deployment.
   c. Create a detailed plan for re-deploying vCenter and reconfiguring your environment.
   d. Follow VMware's official documentation to deploy a new vCenter Server instance.
   e. Reconfigure your environment according to your plan, addressing each complexity factor.

7. Post-Recovery Actions:
   a. Implement or improve your vCenter backup strategy:
      - For vCenter 6.7 and newer, configure file-based backup.
      - Consider additional third-party backup solutions for redundancy.
   b. Document the recovery process and update your disaster recovery plans.
   c. Schedule regular backup testing to ensure recoverability.

Remember: The complexity of your vCenter environment directly impacts the difficulty and duration of a full re-deployment. Regular, tested backups are crucial for minimizing downtime and data loss in severe corruption scenarios.

Additional Information

- File-Based Backup and Restore of vCenter Server

- 6.7: vCenter Server Installation and Setup
- 7.0: vCenter Server Installation and Setup
- 8.0: vCenter Server Installation and Setup

- The vCenter Server and ESXi products have become more resilient over the years. Please be aware that one of the drawbacks of running on the no longer supported 6.x versions is that they are far more subject to corruption issues due to storage and networking communication problems. However, VMware software is not bullet-proof against any environment if it is unhealthy enough. A healthy hardware system is still critical to having a healthy VMware vSphere environment.