Tag: xapi

grub2 help for kernel upgrade on Ubuntu 12.04 domU on XCP

I wouldn’t be posting if this wasn’t yet another corner case, where things don’t work as they should… I likely built my xcp-xapi box at a bad time for xcp-xapi and grub2, hopefully this helps others…

Situation: installing new virtual kernel on Ubuntu 12.04 domU kernel upgrade crashes royally:

Error: Starting VM – Using to parse /boot/grub/grub.cfg – WARNING:root:Unknown directive load_video – WARNING:root:Unknown directive terminal_output – WARNING:root:Unknown directive else – WARNING:root:Unknown directive else – WARNING:root:Unknown directive else – WARNING:root:Unknown directive else – WARNING:root:Unknown directive else – WARNING:root:Unknown directive export – WARNING:root:Unknown image directive recordfail – WARNING:root:Unknown image directive gfxmode – WARNING:root:Unknown image directive recordfail – WARNING:root:Unknown directive submenu – WARNING:root:Unknown image directive recordfail – WARNING:root:Unknown image directive gfxmode – WARNING:root:Unknown image directive recordfail – Traceback (most recent call last): – File “/usr/lib/xcp/lib/pygrub.xcp”, line 853, in – raise RuntimeError, “Unable to find partition containing kernel” – RuntimeError: Unable to find partition containing kernel

Background: Ubuntu 12.04 dom0 running xcp

Work around (http://blog.403labs.com/post/1546501840/paravirtulization-with-citrix-xenserver-5-5-and-ubuntu):

 xe vm-param-set uuid=<VM-UUID> PV-bootloader-args="--kernel=/boot/vmlinuz-3.2.0-29-virtual --ramdisk=/boot/initrd.img-3.2.0-29-virtual"
xe vm-param-set uuid=<VM-UUID> PV-args="root=UUID=<disk-UUID> ro -- console=hvc0"

ubuntu 12.04 xcp bare metal recovery via rsnapshot

I’m verifying my backup process via a bare metal recovery to identical hardware so I thought I’d take some notes…

I got started on my ubuntu xen xcp/xapi setup with this excellent guide:
http://francispereira.com/blog/step-by-step-guide-to-setting-up-xen-and-xenapi-xcp-on-ubuntu-12-04-and-managing-it-with-xencenter/

Booted a usb based rescue disk to partition my disks the same as oringinal dom0, then rsync over the stuff from my dom0 rsnapshot, created /dev /proc and /sys directories, mounted them with –bind and then chrooted on to the actual partition to rebuild grub

sudo grub-install /dev/sdb
sudo grub-install --recheck /dev/sdb
sudo update-grub

Then umounted things and rebooted, and volia… but networking wasn’t happy… after some banging around I discovered my old nemesis the udev persistent crap, who ever thought of this has some explaining to do, how could this have ever been worth it? Maybe I’m just not in the use case where it’s good for my network adapter to seemingly randomly stop working. None the less, a quick

rm of /etc/udev/rules.d/70-persistent-net.rules

and a reboot and things were back to the way they should be. (also updated my rsnapshot exclude list so I can forget about udev for a while).

UPDATE(9/3/12): just booted the box and realized that it was unhappy about UUIDs of the new filesystems (/dev/sda1 (root) and /dev/sda2 (swap) in my case so some grub editing was needed to boot, and then also updating of /etc/fstab and running update-grub.

With xen xcp-xapi on ubuntu we’re pretty much off book so for this portion of the restore I’m planning to clean things out, create a new LVM, and then import from basic generic vxa images, and then restore domU data/settings from rsnapshot.

I cleaned out the xe setup with a number of commands including xe sr-forget, xe vm-destroy, xe pbd-unplug, xe pdb-destroy, xe vdi-destroy, and xe vbd-destroy, also the -list version of the above helps to identify what to destroy.

I recreated the LVM (synopsis of steps from above guide).

fdisk, n, p, 3, , t, 8e, W. #(use the rest of the disk)
pvcreate /dev/sda3
vgcreate VolumeGroup /dev/sda3
pvdisplay #(get size from here)
lvcreate --size G -n LocalStorage VolumeGroup
xe sr-create type=ext name-label=Local Storage device-config:device=/dev/mapper/VolumeGroup-LocalStorage

Next I set the recently created sr as the default SR and imported a vxa. then used nmap to find it, as that’s faster way to find it than logging in to my wrt.

xe sr-list
xe pool-list
xe pool-param-set uuid= default-SR=
xe vm-import filename=.vxa
xe vm-start vm=
nmap -PN -sS 10.0.0.0/24 192.168.1.0/24

I then rsync’ed the domU settings/data back and rebooted. I use the -anv in order to see what it’s going to do before it mucks things up…

rsync -anv --delete --exclude-from= . host:/|less
rsync -a -delete --exclude-from= . host:/

update(9/3/12): also snapshots weren’t working as I needed to specify the default SR

xe sr-list
xe pool-list
xe pool-param-set suspend-image-SR=  uuid=

Things I learned:

  • good to have the output of fdisk
  • I still really hate the udev permanent ethernet crap
  • bunch of xe commands