Changing a forgotten root password on an ESX host

This article provides steps to reset the root password of an ESX host.
Note: This article does not pertain to ESXi. Reinstalling is the only way to reset a root password on ESXi.

ESX 3.x and 4.x
1. Reboot the ESX host.
2. When the GRUB screen appears, press the space bar to stop the server from automatically booting into VMware ESX.
3. Use the arrow keys to select Service Console only (troubleshooting mode).
4. Press the a key to modify the kernel arguments (boot options).
5. On the line presented, type a space followed by the word single.
6. Press Enter. The server continues to boot into single-user mode.
7. When presented with a bash prompt such as sh-2.05b#, type the command passwd and press Enter.
8. Follow the prompts to set a new root user password.
9. When the password is changed successfully, reboot the host using the command reboot and allow VMware ESX to boot normally.

和Linux下操作差不多。
ESXi版本的话就要看这篇文章：http://plaway.blog.51cto.com/872211/253074