Network Boot of Virtual Machines
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Network Boot of Virtual Machines


Article ID: 336879


Updated On:


VMware VMware Desktop Hypervisor VMware vSphere ESXi


This article provides information on setting up a virtual machine to boot from the network.


Controlling network boot

There are two ways to control network boot:
  • Use the F12 and Esc keys to affect the boot order temporarily.
  • Use the F2 key to change the permanent boot order in the BIOS.

During the first phase of bootup, this message appears in the virtual machine:

Press F2 to enter SETUP, F12 for Network Boot, ESC for Boot Menu

If you press F2, you see a setup page. Use the arrow keys to move to the Boot tab and position the cursor on the Network boot option. Press the + key repeatedly to move the Network option to the top position, then press F10 to exit the setup page and save the choice. The virtual machine now boots from the network every time.

If you want to perform an unattended installation of guest operating systems from the network, changing the boot order does not work. It does not work because, after files are copied to the virtual disk, the virtual machine boots again from the network instead of from the disk. In this case, keep the default boot order, which puts the hard drive before the network. When you first start the virtual machine, press F12 to boot from the network. This is a temporary choice. Subsequent boots look for the boot loader on the hard drive before the network, by default.

Another way to perform an unattended installation (for new virtual machines) is to leave the boot order at the default setting. A newly-created virtual machine has an empty virtual boot disk (unless you created it with an existing virtual disk). When the BIOS tries to boot from devices in the default boot order, it first tries the floppy drive. If there is no disk in the drive, it tries the virtual hard drive. If the hard disk is uninitialized, the BIOS tries to do a network boot. In this case, you do not need to press a key during bootup.

If you want to select any boot device on the fly, overriding the permanent boot order, press the Esc key during bootup. A menu of the boot devices in BIOS boot order appears, and you can select any device with the arrow keys. This is also a temporary choice; subsequent boots return to the permanent boot order specified on the setup page.
Delaying Boot
Virtual machine boot can be fast and sometimes may not allow the keyboard input to be received in time. If this is the case, you can modify the virtual machine's .vmx file to introduce a delay in boot.
Note: Make sure that the virtual machine is powered off and that other entries are not touched.
To modify the virtual machine's .vmx:
  1. Open the virtual machine's .vmx file. The default location of the file is C:\Documents and Settings\Username\My Documents\My Virtual Machines\Windows XP Professional.
  2. Modify thebios.bootdelayline so it looks like:
bios.bootDelay = "3000"

The numerical value introduces a 3 second delay in boot. You can change this value as required.

Additional Information

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