From Grid5000

This page describes the Debian based kadeploy environment. This system is derivated from the Debian4all environment with kexec capabilities.

Contents 1 Quick use of kexec 1.1 First step: load the kernel 1.2 Second step: boot the loaded kernel 2 Environment description

Quick use of kexec

kexec is a tool that allow to boot a kernel allong with it's initrd and all the required information passed in the command line. For more information on kexec mechanisms:

http://www-128.ibm.com/developerworks/linux/library/l-kexec.html

To be able to experiment kexec you should deploy the environment debian4kexec (user name that should be given to kadeploy is jleduc on Orsay).

kadeploy -e debian4kexec -l jleduc -p hda6 -f $OAR_NODEFILE 

First step: load the kernel

The first step in kexec is to load the kernel and all the related information. This example shows how to load the same kernel (interesting to see output from kaconsole):

kexec -l /boot/vmlinuz-2.6.16-1-amd64-k8-smp --initrd=/boot/initrd.img-2.6.16-1-amd64-k8-smp /
--command-line="root=/dev/hda6 console=tty0 console=ttyS0,38400n8" --serial=ttyS0 --serial-baud=38400

This example shows how to load the second available kernel from the running system

kexec -l /boot/vmlinuz-2.6.12-1-amd64-k8-smp  --initrd=/boot/initrd.img-2.6.12-1-amd64-k8-smp /
--command-line="root=/dev/hda6 console=tty0 console=ttyS0,38400n8" --serial=ttyS0 --serial-baud=38400

This example shows how to load the deployment kernel from the running system (on e325 nodes):

kexec -l /tmp/duke-vmlinuz.x86 --initrd=/tmp/duke-initrd.x86_64 /
--command-line="ETH_DRV=tg3 ETH_DEV=eth0 DISK_DRV=amd74xx console=tty0 console=ttyS0,38400n8 ramdisk_size=40000" --serial=ttyS0 --serial-baud=38400

Warning You will be only able to do the kexec trick on the 2.6.16-1 kernel: if you try to do the same with the kexeced kernel, the system will reboot.

Second step: boot the loaded kernel

Simply launch:

kexec -e

And watch output from kaconsole.

Environment description