Changing hostname of an ESXi host

Obtain the Direct Console User Interface (DCUI) prompt. Press F2 to enter the system customization menu. You will be asked to enter the root password after which the following display appears:

Select Configure Management Network option. The present configuration is displayed on the right side of the screen. Press enter to edit the network configuration.

Scroll down to DNS configuration & you can see the details on the right side of the screen.

Press enter to go ahead & edit the configuration:

From there go the hostname option & type the new hostname & press enter:

After that you will land at the configure management network prompt again. Press ESC here. Now you will be prompted with the following message:

Entering yes at the above prompt will restart the management network & this will cause a brief network outage for a couple of seconds.