Ubuntu Distribution Upgrade in a OpenVZ Container

If you use Debain Lenny on your OpenVZ host and your Container is a Ubuntu 9.04 and you want to do a apt-get dist-upgrade to 9.10 you will end on the host with this error:

# vzctl enter 1234
enter into VE 1234 failed
Unable to open pty: No such file or directory

What happend? In Ubuntu upstart is responsible for the initialization process but therefore it needs some kernel specific stuff which is not in the 2.6.26 kernel from Debian Lenny. There is a bug report on Launchpad describing the problem.

So on the blog of bodhizazen, the person who started the bug report, you can find the needed upstart script of Stéphane Graber. Like written in bodhizazen blog entry do the following on the host:

cd /var/lib/vz/private/[VZID]/etc/init/
wget http://bodhizazen.net/openvz.conf

Now you can connect again to your virtual ubuntu machine. But if you upgrade from Ubuntu 9.10 to 10.04 you will receive the error message like above.

The solution was found fast, again from Stéphane Graber.

Simply edit /etc/init/openvz.conf and remove the two mount lines for /proc and /sys.

Now you can enjoy your Ubuntu 10.04 LTS container on a Debian Lenny host.