How to upgrade the free ESXi hypervisor to a new version

The steps below are concerning upgrading the free VMware ESXi hypervisor to a new version.  The ESXi host in this example is within a VMware Workstation version 7.1.3 environment.  The upgrade is from version 4.1 to version 4.1 Update 1.

The first component that is required is the VMware vSphere CLI product.  This must be downloaded and installed.  The hypervisor also must be placed into Maintenance Mode before performing the upgrade.  All hosts running on the ESXi host should be shut down before performing this procedure.

Launch the vSphere client.  Connect to the ESXi host in question.  Right-click on the IP address of the ESXi host and select the “Enter Maintenance Mode” option.  The command vicfg-hostops is another method to enter Maintenance Mode as well.

The following dialog box will appear.  Verify all virtual machines running on the hypervisor are shut down and click the Yes button.

If the ESXi host is not within Maintenance Mode, the command to perform the upgrade will fail.

Access the CLI interface via the Start Menu and change to the bin subdirectory.  Download the update and place it in a folder, such as TEMP in this example.  Enter the following command:

perl vihostupdate.pl --server IP address of ESXi host –i –b Path to downloaded .ZIP file

You should be prompted for the user name and password.  The ESXi host will need to be rebooted once the process has completed.  The new version should be visible via the main console screen.