Taking Server Virtualization Down from the Clouds to Real Life Experience: A Journey with ESXi Updates

As a VMware administrator, I have always been fascinated by the possibilities of server virtualization. In recent years, I have had the opportunity to work extensively with ESXi, VMware’s flagship hypervisor, and explore its many features and capabilities. One aspect that has always intrigued me is the process of updating ESXi hosts to keep them current and secure. In this blog post, I would like to share my experiences and insights on how to update ESXi hosts, particularly for standalone hosts, and discuss the benefits and limitations of using maintenance mode.

Update ESXi Hosts: Standalone vs. Managed

When it comes to updating ESXi hosts, there are two main scenarios to consider: standalone hosts and managed hosts. Standalone hosts are not part of a vCenter-managed cluster, while managed hosts are controlled by vCenter and are member of a DRS-enabled cluster. The approach to updating these hosts differs slightly, and it’s essential to understand the differences to avoid any potential issues or downtime.

Updating Standalone ESXi Hosts

For standalone ESXi hosts, it is not necessary to enter maintenance mode before installing updates. In fact, switching to maintenance mode can cause more harm than good, especially if you have running VMs on the host. Instead of using maintenance mode, I recommend using the “VM Autostart/shutdown” feature of ESXi. This feature allows you to automatically shut down VMs when ESXi goes down and power them back on again when it comes up. To enable this feature, follow these steps:

1. Open the ESXi command-line interface (CLI) by running “esxcli” in a terminal window.

2. Run the following command to enable VM autostart/shutdown:

esxcli software vmx -e -n

3. Save the changes and exit the CLI.

Once you have enabled VM autostart/shutdown, you can proceed with installing updates on your standalone ESXi host without needing to enter maintenance mode. The feature will automatically shut down any running VMs before installing the updates and power them back on again after the installation is complete.

Updating Managed ESXi Hosts

For managed ESXi hosts, it is advisable to switch to maintenance mode before installing updates. This ensures that all running VMs are evacuated from the host before the update process begins. To enter maintenance mode on a managed ESXi host, follow these steps:

1. Open the vCenter Server web client and navigate to the “Hosts” tab.

2. Select the ESXi host you want to update and click on the “Maintenance” button in the left-hand menu.

3. Click on the “Enter Maintenance Mode” button to initiate the maintenance mode process.

4. Wait for all running VMs to be evacuated from the host before proceeding with the update process.

Once you have entered maintenance mode, you can install updates on your managed ESXi host as usual. The vCenter Server web client will handle the update process and ensure that all running VMs are safely evacuated before the update begins.

Benefits of Updating ESXi Hosts

Updating ESXi hosts is crucial to maintaining a secure and current infrastructure. Here are some benefits of keeping your ESXi hosts up-to-date:

1. Security updates: ESXi hosts receive regular security updates that address known vulnerabilities and protect against potential attacks.

2. Performance improvements: New versions of ESXi often include performance enhancements that can improve the overall efficiency of your virtualized infrastructure.

3. New features: ESXi updates may introduce new features or functionality that can help you optimize your virtualization strategy and improve your IT operations.

Limitations of Updating ESXi Hosts

While updating ESXi hosts is essential, there are some limitations to consider:

1. Downtime: Entering maintenance mode can cause downtime for running VMs, which may impact your business operations.

2. Compatibility issues: Some custom drivers or software may not be compatible with new versions of ESXi, potentially causing issues during the update process.

3. Rollback issues: If something goes wrong during the update process, rolling back to a previous version may be challenging, especially if you have already applied the updates to multiple hosts.

Conclusion

Updating ESXi hosts is a critical aspect of maintaining a secure and current virtualized infrastructure. While there are some limitations to consider, the benefits of updating your ESXi hosts far outweigh the risks. By understanding the differences between standalone and managed ESXi hosts and using the appropriate method for updating each type, you can ensure a successful update process with minimal downtime and disruption to your business operations.