Understanding the PXE boot process can help you during troubleshooting.
- Most Linux distributions include a copy of the tftp-hpa server. If you require a supported solution, purchase a supported TFTP server from your vendor of choice. You can also acquire a TFTP server from one of the packaged appliances on the VMware Marketplace.
If your TFTP server runs on a Microsoft Windows host, use tftpd32 version 2.11 or later. See http://tftpd32.jounin.net/.
SYSLINUX, PXELINUX, and gPXELINUX
- SYSLINUX is an open-source boot environment for machines that run legacy BIOS firmware. The ESXi boot loader for BIOS systems, mbootc.32, runs as a SYSLINUX plugin. You can configure SYSLINUX to boot from several types of media, including disk, ISO image, and network. You can find the SYSLINUX package at http://www.kernel.org/pub/linux/utils/boot/syslinux/.
- PXELINUX is a SYSXLINUX configuration for booting from a TFTP server according to the PXE standard. If you use PXELINUX to boot the ESXi installer, the pxelinux.0 binary file, mboot.c32, the configuration file, the kernel, and other files are transferred by TFTP.
- gPXELINUX is a hybrid configuration that includes both PXELINUX and gPXE and supports booting from a Web server. gPXELINUX is part of the SYSLINUX package. If you use gPXELINUX to boot the ESXi installer, only the gpxelinux.0 binary file, mboot.c32, and the configuration file are transferred by TFTP. The remaining files are transferred by HTTP. HTTP is typically faster and more reliable than TFTP, especially for transferring large amounts of data on a heavily loaded network.
UEFI PXE and iPXE
Most UEFI firmware natively includes PXE support that allows booting from a TFTP server. The firmware can directly load the ESXi boot loader for UEFI systems, mboot.efi. Additional software such as PXELINUX is not required.
iPXE can also be useful for UEFI systems that do not include PXE in firmware and for older UEFI systems with bugs in their PXE support. For such cases, you can try installing iPXE on a USB flash drive and booting from there.
Alternative Approaches to PXE Booting
- Configuring the DHCP server to provide different initial boot loader filenames to different hosts depending on MAC address or other criteria. See your DCHP server's documentation.
- Approaches using iPXE as the initial bootloader with an iPXE configuration file that selects the next bootloader based on the MAC address or other criteria.