Usage ===== Do $ man 8 kexec for full understanding of the underlying kexec command. Gentoo offers a wrapper to the bare kexec command through /etc/init.d/kexec. Configuration ------------- Configuration is done in /etc/conf.d/kexec, which is self-documented. Usage ----- In Gentoo, kexec is invoked, i.e., the new kernel will be booted when rebooting, by reboot (8) command or by pressing Ctrl+Alt+Del. If you want to use kexec once, just run $ /etc/init.d/kexec start It'll reserve kexec call at reboot. Later on, you can reboot anytime, letting kexec starts another (or the same) kernel. When all is done in the runlevel 6 - killing processes, unmounting volumes, etc - kexec starts the new kernel instead of doing the normal hardware reboot. If you want kexec to be run every time you reboot, add it to a runlevel: $ rc-update add kexec If you want to reboot in the normal way this time, do: $ touch /nokexec