The Steps for PXE Booting

Pre-Boot Execution Environment (PXE):

  • Derived from DHCP
  • Implemented in the NIC and BIOS
  • Used to load Operating System images onto a target computer
  • Requires NIC capable of PXE (e.g. Intel® 82574L Gigabit Ethernet Controller)

PXE Booting Steps - description below

Image Description

  1. Boot order set in BIOS
  2. Universal Network Driver Interface loaded from NIC
  3. PXE client broadcasts a request for an IP address
  4. DHCP server responds with an IP address
  5. PXE client requests name of boot image
  6. Boot server responds with boot image filename
  7. TFTP request from PXE client for the NBP file
  8. TFTP reply from Boot Server
  9. Boot Server sends the boot image file NBP to client
     

Hardware Required for PXE

  • We needed NICs to support PXE booting and Wake on LAN
  • Ordered Intel® 82574L Gigabit Ethernet Controller (qty 3)
  • Cost ~$40-50 each
  • Installed NICs and current Intel driver
     

Features and Benefits of the Intel® 82574L Gigabit Ethernet Controller:

  • Compatible with Fast Ethernet and Ethernet
  • 10/100/1000 Mbps auto-negotiation
  • Support for most network operating systems
  • Advanced configuration and power interface (ACPI)
  • Wake on LAN* (WoL); Preboot Execution Environment (PXE)
  • Allows low-power consumption, remote wake, and remote booting
  • Remote management support
  • Intel® PROSet Utility for Microsoft* Device Manager
  • Advanced cable diagnostics
  • Intel backing
  • Optimized queues: 2 Transmit (Tx) and 2 Receive (Rx)
  • MSI-X support
     

PXE Setup and Diskless Hosts

In our environment, the host systems, or lab desktop workstations, must be prepared in advance for a virtual state:

To do this, the systems are set up to PXE boot:

  • The boot order is set in BIOS
  • Devices are set to Wake on LAN
  • Systems will be diskless (local hard drive not accessed)
  • Systems will boot ESXi 5.5 into RAM from TFTP server


Diskless hosts:

  • No local disk needed
  • Requires PXE bootable system
  • Loads OS into RAM from network
  • Install and post-install configuration not persistent
  • Persistent storage required to save changes


Wake on LAN

Lan with PXE boot is the third choice

The above image displays the BIOS settings required for the NIC in order to Wake on LAN. 
NOTE: Machines must be shut off in order for ESXI to boot on wake-up. If the machine is asleep it will boot to the installed OS.

To Setup Wake on LAN for the NIC:

  • Open Network and Sharing Center
  • Select Local Area Connection
  • This opens a "Local Area Connection Status" window
  • Select Properties
  • Select the Configure button
  • This opens the "Intel Gigabit CT Desktop Adapter Properties" window
  • Select the Power Management Tab
  • Configure Wake on LAN settings as displayed here
     

Configure the PXE Service Point

In order to share the lab equipment between a virtualized lab designed for remote users and a classroom setting for DTCC students physically on campus, we had to determine how to get systems to move from one working state to another and automate the process (i.e. power on/off, Windows 7 on local drive to ESXi 5.5 running in memory). There are several scenarios outlined below of a possible workstation state and items to consider regarding changing the state and security.

Requirements

  • PCs boot in the morning with BIOS
  • PC restarts/boots with ESXi in the evening
  • PC shuts down ESXi at night.
     

PC States

  • Off
  • Running lab OS (Windows 7)
  • Running ESXi 5.5
     

There are three possible outcomes:

  1. PC boots in morning from OFF to lab OS (Windows 7)
    • Done in BIOS through auto power on settings
    • Local HDD is accessed
    • BIOS can be locked with password for added security
  2. PC boots in evening from OFF to ESXi
    • PCs will need to be manually shut down at the end of the last class each day
    • Using Wake on Lan magic packet
    • PC is woken at specified time in the evening (ex. 6 pm)
    • PXE boot request is fulfilled
    • ESXi image is pushed out to PC
  3. Shutdown PC at night from ESXi
    • Set up script using PowerCLI to shutdown PC from vCenter Server
    • VMs are shutdown then the host
    • Clean shutdown requires that VMs have VMware Tools installed

Configuring Scheduling:

  • Configuring lab computers for PXE booting and Wake on LAN
  • Onboard: Set BIOS to enable PXE booting and Wake on LAN, and also enable PXE booting and Wake on LAN in internal NIC settings in the BIOS
  • NIC Card: Set BIOS to enable PXE booting and Wake on LAN; next configure the NIC card in Windows Device Manager settings, under Power Management set Wake on Magic Packet, Wake on Pattern Match, and Wake on Magic Packet from power off state