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pxechaining [2009/02/17 16:41] mcb30 |
pxechaining [2010/07/14 13:09] (current) vutcovici |
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| ====== PXE chainloading ====== | ====== PXE chainloading ====== | ||
| + | |||
| + | If you have a large number of machines which already have a legacy PXE implementation (e.g. network cards containing an Intel PXE ROM), then you may want to avoid having to reflash each machine's network card. You can achieve this by placing gPXE on your TFTP server. The PXE-capable machines will download gPXE via TFTP, and instantly become gPXE-capable machines. | ||
| {{ :screenshots:gpxe-chaining.png?361x201|PXE chainloading in VMware}} | {{ :screenshots:gpxe-chaining.png?361x201|PXE chainloading in VMware}} | ||
| - | If you have a large number of machines which already have a legacy PXE implementation (e.g. network cards containing an Intel PXE ROM), then you may want to avoid having to reflash each machine's network card. You can achieve this by placing gPXE on your TFTP server. The PXE-capable machines will download gPXE via TFTP, and instantly become gPXE-capable machines. | + | === UNDI Driver === |
| + | Universal Network Device Interface (UNDI) is an application programming interface (API) for network interface cards (NIC) used by the Preboot Execution Environment (PXE) protocol. | ||
| + | |||
| + | When chainloading gPXE from PXE, gPXE can use this API (instead of loading an hardware driver). This way, you're getting support for network controllers that are not natively supported by gPXE. some network controllers have improved performance when using the UNDI driver over the vendor specific gPXE driver (forcedeth for example). | ||
| + | |||
| + | To use the UNDI driver, select the UNDI driver (undionly) when generating the gPXE ROM. | ||
| ===== Setting up PXE chainloading ===== | ===== Setting up PXE chainloading ===== | ||
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| If you are running ISC dhcpd as your DHCP server, then edit ///etc/dhcpd.conf// to contain | If you are running ISC dhcpd as your DHCP server, then edit ///etc/dhcpd.conf// to contain | ||
| - | if not ( option user-class = "gPXE" ) { | + | if exists user-class and option user-class = "gPXE" { |
| + | filename "http://my.web.server/real_boot_script.php"; | ||
| + | } else { | ||
| filename "undionly.kpxe"; | filename "undionly.kpxe"; | ||
| } | } | ||
| | | ||
| - | filename "http://my.web.server/real_boot_script.php"; | ||
| - | |||
| This will ensure that the gPXE image (//undionly.kpxe//) is handed out only when the DHCP request comes from a legacy PXE client. Once gPXE has been loaded, the DHCP server will direct it to boot from //%%http://my.web.server/real_boot_script.php%%//. | This will ensure that the gPXE image (//undionly.kpxe//) is handed out only when the DHCP request comes from a legacy PXE client. Once gPXE has been loaded, the DHCP server will direct it to boot from //%%http://my.web.server/real_boot_script.php%%//. | ||
| + | ==== Using dnsmasq ==== | ||
| + | Dnsmasq is a DHCP, TFTP, DNS server. Here is the configuration for chain loading gPXE. | ||
| + | |||
| + | The conf is: | ||
| + | #DHCP part | ||
| + | domain=mydomain | ||
| + | dhcp-range=192.168.10.100,192.168.10.200,255.255.255.0,30m | ||
| + | dhcp-option=option:router,192.168.10.1 | ||
| + | dhcp-authoritative | ||
| + | | ||
| + | # TFTP part | ||
| + | enable-tftp | ||
| + | tftp-root=/tftproot | ||
| + | | ||
| + | # host part, a VM that will be booted from network | ||
| + | # 00:0C:29 - the MAC part of VMware vendor - we are booting a VM | ||
| + | # here we chainload gPXE | ||
| + | dhcp-host=00:0c:29:aa:bb:cc,gPXE-client,net:gPXE-testVM,192.168.10.100,10m | ||
| + | dhcp-boot=net:gPXE-testVM,undionly.kpxe | ||
| + | # for a gPXE enabled client we are asking him to boot from a image located at an URL. The image can be a gPXE script | ||
| + | dhcp-userclass=gPXE-booted,"gPXE" | ||
| + | dhcp-boot=net:gPXE-booted,http://my.web.server/real_boot_script.php | ||
| + | |||
| + | The file undionly.kpxe is located in the /tftproot/ folder. | ||
| + | To build undionly.kpxe run: | ||
| + | wget http://kernel.org/pub/software/utils/boot/gpxe/gpxe-1.0.1.tar.bz2 | ||
| + | tar jxf gpxe-1.0.1.tar.bz2 | ||
| + | cd gpxe-1.0.1/src | ||
| + | make DEBUG=http,iscsi,tftp,dhcp bin/undionly.kpxe&&sudo cp bin/undionly.kpxe /tftproot/undionly.kpxe | ||
| + | |||
| + | ==== Using pxelinux, menu.c32 and dnsmasq to chainload gPXE ==== | ||
| + | If you want to test gPXE but you are using extensively pxelinux and you do not want to break the rest of your configuration, you can add a menu entry to load gPXE. | ||
| + | The ''/etc/dnsmasq.conf'' should contain something like: | ||
| + | #DHCP | ||
| + | domain=mydomain | ||
| + | dhcp-range=192.168.10.100,192.168.10.200,255.255.255.0,30m | ||
| + | dhcp-option=option:router,192.168.10.1 | ||
| + | dhcp-authoritative | ||
| + | | ||
| + | # TFTP part | ||
| + | enable-tftp | ||
| + | tftp-root=/tftproot | ||
| + | | ||
| + | # PXE | ||
| + | dhcp-boot=/tftproot/pxelinux.0 | ||
| + | # required by old versions of gPXE (e.g. the one that comes with OracleVM) | ||
| + | dhcp-no-override | ||
| + | The ''/tftproot/pxelinux.cfg/default'' should contain: | ||
| + | DEFAULT menu.c32 | ||
| + | PROMPT 1 | ||
| + | | ||
| + | LABEL gpxe | ||
| + | MENU LABEL gPXE - chainload gPXE from a PXE capable NIC | ||
| + | KERNEL undionly.0 | ||
| + | On an Ubuntu system install ''syslinux'' package and make ''/tftproot/pxelinux.0'' symlink to ''/usr/lib/syslinux/pxelinux.0''. | ||
| + | The file ''/tftproot/undionly.0'' is a symlink to ''/tftproot/undionly.kpxe''. | ||
| ==== Using the Windows DHCP server ==== | ==== Using the Windows DHCP server ==== | ||
