Debian4kexec

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

Contents

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

Debian4kexec

  • Based on: Debian version testing/unstable for pure 64 bits
  • Reference file: /home/grenoble/jleduc/Images/image_debian4kexec.tgz at Orsay (md5sum is b6f0d6d8aaf852f72a3f0f941e5b2bb2)
  • Valid on: HP DL145G2, IBM e325, Sun v20z, IBM e326

Kernel version 2.6.16-1 from Debian for x86_64

Authentication

  • Remote console: on ttyS0 at 38400 bps
  • Services: ldap:no, nfs:no
  • Accounts: root:grid5000,

Applications

  • ssh has X11 forwarding enabled
  • Text Editors:echo, sed, vi, vim

Misc

  • source-list configured for all grid5000 sites
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