Overview
Updating a debian etch (v4.1) system to lenny (v5.0) also involves an upgrade of xen from v3.0 to v3.2. This can create quite some hassle for specific setups.
The documentation below describes some of the issues, that we ran into, when we upgraded the https://systemausfall.org server.
The xen network setup
Our xen network setup is not very common. Thus it should be helpful to give you a short introduction.
Problematic details
Update the kernel
Update the kernel link for all domU
To ease the maintenance of the domU kernel during upgrades, we use symlinks in /boot:
thorax:~# ls -l /boot lrwxrwxrwx 1 root root 35 2008-12-28 05:20 domU-initrd -> /boot/initrd.img-2.6.18-6-xen-amd64 lrwxrwxrwx 1 root root 32 2008-12-28 05:20 domU-kernel -> /boot/vmlinuz-2.6.18-6-xen-amd64 -- snipped some more details --
Update these links to the new domU kernel:
lrwxrwxrwx 1 root root 35 2008-12-28 05:20 domU-initrd -> /boot/initrd.img-2.6.26-1-xen-amd64 lrwxrwxrwx 1 root root 32 2008-12-28 05:20 domU-kernel -> /boot/vmlinuz-2.6.26-1-xen-amd64
Make sure, that all xen host configuration files (e.g. in /etc/xen/ or /etc/xen/vm/) contain the following lines:
kernel = '/boot/domU-kernel' ramdisk = '/boot/domU-initrd'
Update the configuration file of xen-tools (/etc/xen-tools/xen-tools.conf) to use these kernel symlinks by default for new xen hosts:
kernel = /boot/domU-kernel initrd = /boot/domU-initrd #kernel = /boot/vmlinuz-`uname -r` #initrd = /boot/initrd.img-`uname -r`
Update the new module directory in all domU
- shutdown all xen hosts
- mount the system partitions of the xen hosts
copy the new modules directory:
cp -a /lib/modules/`uname -r` $MNT_DIR/lib/modules/
No terminal for ssh login
Behaviour
Login to domU hosts via ssh fails with the following output:
PTY allocation request failed on channel 0 stdin: is not a tty
Even xm console $HOST_NAME stops before the login prompt.
Workaround
Debian bug [http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=502798 #502798] suggests to add the following lines to the configuration file of each domU:
# necessary for ssh login since lenny # see http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=502798 extra = "console=hvc0"
This allows to login via ssh, but xm console still does not work.
Broken network interfaces in dom0
Our