pxe-kexec - Read PXE configuration file and kexec entries
pxe-kexec [options] [ tftp_server
is a tool that fetches PXE configuration from a TFTP server,
reads that PXE configuration file, prompts the user for an boot entry,
downloads the specified kernel and initrd and finally tries to boot the
The normal process to boot with kexec
(8) is that pxe-kexec loads the
kernel and invokes reboot
(8). The shutdown script of the Linux
distribution then executes "kexec -e" at the very end. That is not
implemented everywhere. Therefore, pxe-kexec has a whitelist of Linux
distributions that support reboot with kexec. If the distribution is not on
that whitelist, the program quits with a warning. To bypass that warning,
please use the "--igore-whitelist" parameter. You can also use the
"--force" parameter to execute "kexec -e" to immediately
boot the selected kernel, without invoking
pxe-kexec meant to be used in an environment where pre-defined PXE
configurations exist but the user wants to use kexec
(8) instead of
Normally, the tftp_server
must be specified as first argument. If there's
no TFTP server specified, pxe-kexec looks in the DHCP info file for the DHCP
server and uses this one as TFTP server. This only works when the TFTP server
is running on the same machine as the DHCP server.
==> Please also read the section called "Update Info" <==
As mentioned previously, a whitelist of Linux distributions that support
kexec-based rebooting is maintained. Currently following distributions are on
- openSUSE, starting with version 11.0
- Ubuntu, starting with version 9.04
- Red Hat Enterprise Linux and CentOS, starting with version
- Fedora Linux, starting with version 11
- ARCH Linux
Don't hesitate to send the author an email to add the distribution to the
whitelist. Please include the output of "pxe-kexec
--print-distribution" in that mail.
Following options can be specified:
- -h | --help
- Prints a short help.
- -v | --version
- Prints the version number to standard output.
- -f | --force
- Immediately load the kernel without invoking
reboot(8). This does not execute shutdown scripts, i.e. does not
terminate daemons, network connections etc.
- -L | --load-only
- When that option is specified, the new kernel is only
loaded. No reboot is triggered and "kexec -e" is also not
- -w | --ignore-whitelist
- Don't check if the detected Linux distribution is on the
whitelist of distributions that have kexec(8) in their shutdown
script. Please don't use that parameter without letting the author know
which distribution you use and how to detect that distribution. Then the
distribution can be added to the whitelist and other users profit from
- -l label | --label label
- Specifies the label that should be booted. Use that option
if you already know which label you want to boot. This option
- -i | --interface netif
- Uses netif instead of the first (non-loopback and
up) interface that is found. Example: "eth5".
- -n | --noconfirm
- Don't ask the user for confirmation before booting an
entry. Use that option with care!
- -Y | --dry-run
- Don't execute call to kexec and don't switch the virtual
console before running "kexec -e". Instead, print the
information which program would be executed with which arguments to
- -q | --quiet
- Don't display the PXE messages that are added in the PXE
configuration with the say keyword. Also don't display messages
which PXE configuration files the downloader tries to fetch.
- -p | --print-distribution
- Only prints the detected Linux distribution and exits. For
Type : Ubuntu
Name : Ubuntu
Release : 9.04
Codename : jaunty
Description : Ubuntu 9.04
This option is very useful if your distribution is not on the whitelist of
Linux distributions that support kexec(8) in the reboot scripts and
you want to create a bugreport.
This command does not require root privileges.
- -D | --debug
- Enable debugging output. That's good for finding (and
- -d | --nodelete
- Keep downloaded files.
- -F | --ftp
- Always use FTP instead of TFTP. Useful for servers that
share TFTP root and FTP root. (Passive) FTP has the advantage that it
passes firewalls better than TFTP.
Compared to version 0.1.x, the syntax has changed:
- The default label must now be set with the -l
label option instead of the 2nd argument. Example:
% pxe-kexec mydhcp.mydomain.com SLES10-install-auto
% pxe-kexec -l SLES10-install-auto mydhcp.mydomain.com
- pxe-kexec now uses the reboot mechanism by default: The
kernel is loaded, then the reboot is triggered and the reboot script of
the Linux distribution finally boots the kernel. This has the advantage of
a clear shutdown.
The program keeps a database of Linux distributions that support kexec-based
reboot. If the currently active distribution is not on the whitelist, an
error is printed. (That whitelist can be ignored with
- To use the previous behaviour, i.e. just execute
"kexec -e" in pxe-kexec at the end, you can still use the
"--force" parameter. Example:
% pxe-kexec mydhcp.mydomain.com
% pxe-kexec --force mydhcp.mydomain.com
- If you want to have the old "dry-run" behaviour
back, which in fact only missed the last "kexec -e" step, you
can use the option "--load-only". Example:
% pxe-kexec --dry-run mydhcp.mydomain.com
% pxe-kexec --load-only mydhcp.mydomain.com
- Try to fetch the PXE configuration from
mydhcp.mydomain.com, display the say messages from that
configuration, prompt for an entry, letting the user confirm that entry
and finally load that entry via kexec(8) and reboot via
This only works if you distribution supports kexec-based rebooting, i.e. it
is in the internal whitelist.
- pxe-kexec -n
- Same as the previous example, but omit the final
- pxe-kexec -l SLES10-install-auto
- Same as the first example, but don't prompt the user for
the label to boot. Directly boot the SLES10-install-auto label, but
letting the user confirm that he really wants to boot this!
- pxe-kexec -n -l SLES10-install-auto
- Same as the previous example, but without
- pxe-kexec -f
- Same as the first example, but execute "kexec -e"
at the end instead of invoking reboot(8).
- pxe-kexec -l
- Same as the first example, but don't trigger a reboot.
Instead, the kernel is just loaded. If your distribution supports
kexec-based rebooting, the kernel will be loaded on next reboot. You can
also run "kexec -e" manually at any time.
program and documentation has been written by Bernhard
This program has no bugs. If you find a feature that should be removed, please
report to <email@example.com> if you don't want to create an account.