To 'uninstall' an ESXi patch, you typically perform a rollback to the previously installed ESXi build, especially if the patch introduces unexpected issues. ESXi hosts maintain a boot bank of the prior successful installation, allowing for a return to a stable state.
Rolling Back an ESXi Patch Manually During Boot
This method involves interacting directly with the ESXi host console during the boot process and is often the most direct way to revert a problematic patch.
Step-by-Step Manual Rollback Process
- Prepare and Reboot the Host:
- Before starting, ensure all virtual machines (VMs) on the ESXi host are either powered off, migrated to another host using vMotion, or suspended to prevent data loss.
- Access the ESXi Direct Console User Interface (DCUI). This can be done directly from the physical console or via a remote management interface like iLO, iDRAC, or vSphere Client's console for the host.
- From the DCUI, you can initiate a reboot. Press F12 to view the shutdown options for the ESXi host, then Press F11 to reboot the host. Confirm the reboot if prompted.
- Access the Rollback Option:
- As the ESXi host reboots, pay close attention to the purple boot screen.
- During this phase, you will typically see an option, often prompted by pressing
Shift+R, to enter Recovery Mode or view advanced boot options. Press this key combination quickly before the standard boot process proceeds.
- Confirm and Initiate Rollback:
- Once in the Recovery Mode menu, you will be presented with options, including booting the current ESXi build or reverting to the previous build. Select the option to roll back to the earlier ESXi version.
- You will be prompted to confirm your choice. Press Y to roll back the build. This action signals the system to load the previously stable ESXi installation.
- Boot the Previous Build:
- After confirming the rollback, the host will begin loading the chosen previous ESXi installation. Press Enter to boot from this rolled-back version.
Important Note: This process reverts the entire ESXi installation to the state it was in before the last patch or update was applied. All changes introduced by that specific patch will be undone.
When to Consider Manual Rollback
- Immediate Critical Issues: If a recently applied patch causes the host to become unstable, unmanageable, or introduces critical service disruptions shortly after installation.
- No vCenter/vLCM Access: When vCenter Server or vSphere Lifecycle Manager (vLCM) is unavailable or compromised, preventing automated remediation.
- Targeted Reversion: For a quick, direct reversion of the last applied patch.
Best Practices for ESXi Patching to Minimize Rollback Needs
To reduce the necessity of performing a rollback, adopting proactive patch management strategies is crucial.
1. Always Enter Maintenance Mode
Before applying any patches or updates, always place the ESXi host into maintenance mode. This ensures that no virtual machines are running on the host, preventing service interruptions and data corruption during the patching process.
2. Host Configuration Backup
Before applying patches, back up your ESXi host configuration. Tools like vicfg-cfgbackup or even the built-in backup functionality in vCenter Server (for host profiles) can save your host's configuration, allowing for a quicker restore if a full host rebuild becomes necessary.
3. Utilize a Test Environment
Whenever possible, test patches in a non-production or lab environment that mirrors your production setup. This helps identify potential compatibility or stability issues before they impact your live infrastructure.
Broader Patch Management Strategies
While manual rollback is a reactive measure, modern vSphere environments offer more sophisticated tools for proactive and managed patching.
1. Leveraging vSphere Lifecycle Manager (vLCM)
For environments with vCenter Server, vSphere Lifecycle Manager (vLCM) is the recommended tool for managing ESXi host updates. vLCM uses desired state configurations, image baselines, and can perform staged updates, ensuring compliance and simplifying remediation. While it doesn't offer a direct "uninstall patch" button in the same way as a manual rollback, it enables you to revert to a previous baseline or ensure hosts conform to a known good state.
2. Host Profiles
VMware Host Profiles are powerful tools for standardizing and managing host configurations across multiple ESXi hosts. While not directly for patch rollback, they can help ensure that if a host's configuration deviates after a patch or issue, it can be quickly brought back into compliance with a predefined, stable profile.
Important Considerations After Rollback
- Root Cause Analysis: After successfully rolling back, investigate why the patch caused issues. Was it a compatibility problem, a bug, or an environmental factor?
- Documentation: Document the rollback, the reasons for it, and any actions taken.
- Reapply Cautiously: If you decide to reapply the patch later, do so with caution, perhaps after a vendor fix or after addressing identified underlying issues.
Key Actions for ESXi Patch Management
| Action | Description | When to Use |
|---|---|---|
| Manual Rollback | Revert the ESXi host to its previous build state via the boot menu. | Critical post-patch issues, no vCenter access. |
| Maintenance Mode | Prevent VMs from running on the host during patching. | Before applying any patches. |
| Host Configuration Backup | Save host settings to easily restore if a rebuild is needed. | Before applying any patches. |
| Test Environment | Apply patches in a non-production environment first. | Before applying to production. |
| vSphere Lifecycle Manager | Automated, policy-driven patch management and desired state configuration. | For ongoing patch management in vCenter environments. |
