So my first Centos 5.1 to Centos 5.2 upgrade on a VPS didn’t go so well.

After “yum update” and a reboot, we see:

[/sbin/fsck.ext3 (1) — /] fsck.ext3 -a /dev/sda1
/dev/sda1:
The superblock could not be read or does not describe a correct ext2
filesystem. If the device is valid and it really contains an ext2
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate
superblock:
e2fsck -b 8193

Followed by:

Give root password for maintenance
(or type Control-D to continue):

How not very nice!

It seems the UDEV and XEN aren’t playing nicely, I’ve had problems with UDEV and OPENVZ in the past. Could also be to do with the kernel versions running on the DOM0. Anyways…

umount / <--- un-mount the file system mount -n -o remount, rw / <--- mount the file system in read/write

To disable udev in CentOS 5 you edit /etc/rc.d/rc.sysinit file and comment out the line: /sbin/start_udev

Didn’t work for me though, things must have been a bit messed up, so to get going I used.

/bin/mknod /etc/udev/devices/sda b 8 0
/bin/mknod /etc/udev/devices/sda1 b 8 1

After a reboot we were back in business, or are we…

INIT: no more processes left in this runlevel
INIT: Switching to runlevel: 6

LOL… or not 😐

Even more udev breakage that can be fixed with:

/bin/mknod /dev/null c 1 3
/bin/mknod /dev/random c 1 8
/sbin/MAKEDEV tty
/sbin/MAKEDEV pty

Bah!