Difference between pages "Conversion" and "Pxe"
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| − | + | '''PXE''' stands for '''P'''reboot E'''x'''ecution '''E'''nvironment. It is used to boot a computer using booting information from over the network. | |
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| − | = | + | = Overview = |
| + | The typical PXE boot looks like this: | ||
| + | # Computer ''A'' starts. Its [http://en.wikipedia.org/wiki/BIOS BIOS] is set to do a PXE [[boot]], so booting from the network. | ||
| + | # Computer ''A'' acquires an IP address from [[dhcp]] [[server]] ''B''. | ||
| + | # Computer ''A'' downloads its booting files ([[initrd]] and [[kernel]]) via [[tftp]] from ''B''. | ||
| + | # Computer ''A'' executes the kernel just as if it had from its local [[hard disk]]. | ||
| − | = | + | = How to start = |
| − | + | In this example we use SUSE Linux 12.1. | |
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| − | == | + | == DHCP == |
| − | + | To allow your computers to boot from the network, they first need an IP address. So, [[set up a dhcp-server]]. Make sure /etc/dhcpd.conf contains the following lines: | |
| + | allow booting; | ||
| + | allow bootp; | ||
| + | authoritative; # I am the one and only here | ||
| + | Make sure your "subnet" section contains the following lines: | ||
| + | next-server ''192.168.0.5''; | ||
| + | filename "pxelinux.0"; | ||
| + | Make sure you have restarted your dhcpd: | ||
| + | /etc/init.d/dhcpd restart | ||
| − | = | + | == TFTP == |
| − | + | After your computers have received their IP address, they start asking for their booting file from the TFTP-server, in this case ''192.168.0.5''. So, make sure they can get it. | |
| + | * [[Install]] tftp and syslinux: | ||
| + | # yast -i tftp syslinux | ||
| + | * copy syslinux' pxelinux.0 to /srv/tftpboot/: | ||
| + | # rpm -ql syslinux | grep pxelinux.0 | ||
| + | /usr/share/syslinux/gpxelinux.0 | ||
| + | /usr/share/syslinux/pxelinux.0 | ||
| + | # cp /usr/share/syslinux/pxelinux.0 /srv/tftpboot/ | ||
| + | * Activate the tftp server. To do this, change /etc/xinetd.d/tftp. Replace | ||
| + | disable = yes | ||
| + | with | ||
| + | disable = no | ||
| + | Then restart xinetd which hosts tftpd: | ||
| + | /etc/init.d/xinetd restart | ||
| + | * Test it: | ||
| + | tftp ''192.168.0.5'' -c get pxelinux.0 | ||
| + | Test your configuration now by booting a connected computer from PXE. You should get an error message saying that the configuration file pxelinux.cfg/default has not been found. | ||
| − | == | + | == pxelinux.cfg/default == |
| − | + | Create a /srv/tftpboot/pxelinux.cfg/default like this: | |
| + | default linux | ||
| + | timeout 0 | ||
| + | prompt 1 | ||
| + | display display.msg | ||
| + | |||
| + | label linux | ||
| + | kernel vmlinuz | ||
| + | append initrd=initrd | ||
| − | + | * Now you must supply kernel (vmlinuz) and initrd into the tftp folder: | |
| + | cp /boot/vmlinuz /srv/tftpboot | ||
| + | cp /boot/initrd /srv/initrd | ||
| − | [[ | + | == Change initial ramdisk == |
| + | If you now want to change the initrd to actually do something, you can do it like this: | ||
| + | cd /tftpboot | ||
| + | mkdir tmp | ||
| + | cd tmp | ||
| + | cp ../initrd.img ./initrd.gz | ||
| + | gunzip initrd.gz | ||
| + | mkdir tmp2 | ||
| + | cd tmp2 | ||
| + | [[cpio]] -id < ../initrd | ||
| + | Do the needed changes now in this folder. Then pack the initrd again: | ||
| + | [[find]] . | cpio --create --format='newc' > ../newinitrd | ||
| + | cd .. | ||
| + | [[gzip]] newinitrd | ||
| + | Your new [[initrd]] is now called newinitrd.gz. | ||
| − | == | + | = See also = |
| − | + | * [http://en.wikipedia.org/wiki/Preboot_Execution_Environment Wikipedia on PXE] | |
| + | * http://www.digitalpeer.com/id/linuxnfs | ||
| − | + | [[Category:Networking]] | |
| − | + | [[Category:Boot]] | |
| − | + | [[Category:Guides]] | |
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Revision as of 13:13, 9 December 2012
PXE stands for Preboot Execution Environment. It is used to boot a computer using booting information from over the network.
Contents
Overview
The typical PXE boot looks like this:
- Computer A starts. Its BIOS is set to do a PXE boot, so booting from the network.
- Computer A acquires an IP address from dhcp server B.
- Computer A downloads its booting files (initrd and kernel) via tftp from B.
- Computer A executes the kernel just as if it had from its local hard disk.
How to start
In this example we use SUSE Linux 12.1.
DHCP
To allow your computers to boot from the network, they first need an IP address. So, set up a dhcp-server. Make sure /etc/dhcpd.conf contains the following lines:
allow booting; allow bootp; authoritative; # I am the one and only here
Make sure your "subnet" section contains the following lines:
next-server 192.168.0.5; filename "pxelinux.0";
Make sure you have restarted your dhcpd:
/etc/init.d/dhcpd restart
TFTP
After your computers have received their IP address, they start asking for their booting file from the TFTP-server, in this case 192.168.0.5. So, make sure they can get it.
- Install tftp and syslinux:
# yast -i tftp syslinux
- copy syslinux' pxelinux.0 to /srv/tftpboot/:
# rpm -ql syslinux | grep pxelinux.0 /usr/share/syslinux/gpxelinux.0 /usr/share/syslinux/pxelinux.0 # cp /usr/share/syslinux/pxelinux.0 /srv/tftpboot/
- Activate the tftp server. To do this, change /etc/xinetd.d/tftp. Replace
disable = yes
with
disable = no
Then restart xinetd which hosts tftpd:
/etc/init.d/xinetd restart
- Test it:
tftp 192.168.0.5 -c get pxelinux.0
Test your configuration now by booting a connected computer from PXE. You should get an error message saying that the configuration file pxelinux.cfg/default has not been found.
pxelinux.cfg/default
Create a /srv/tftpboot/pxelinux.cfg/default like this:
default linux timeout 0 prompt 1 display display.msg label linux kernel vmlinuz append initrd=initrd
- Now you must supply kernel (vmlinuz) and initrd into the tftp folder:
cp /boot/vmlinuz /srv/tftpboot cp /boot/initrd /srv/initrd
Change initial ramdisk
If you now want to change the initrd to actually do something, you can do it like this:
cd /tftpboot mkdir tmp cd tmp cp ../initrd.img ./initrd.gz gunzip initrd.gz mkdir tmp2 cd tmp2 cpio -id < ../initrd
Do the needed changes now in this folder. Then pack the initrd again:
find . | cpio --create --format='newc' > ../newinitrd cd .. gzip newinitrd
Your new initrd is now called newinitrd.gz.
