I switched one server from Fedora Core to Ubuntu yesterday. Shibboleth 2 SP installation is a bit more tricky under Ubuntu than Fedora Core. The packages are not available in the Ubuntu repositories, but Satya's blog serves a working howto.

failed to bind to socket

Shibboleth seemed to be working well after installation, but today it was down dumping

2009–06–23 12:51:53 ERROR Shibboleth.Listener : socket call resulted in error (2): no message 2009–06–23 12:51:53 CRIT Shibboleth.Listener : failed to bind to socket.

into the /var/log/shibboleth/shibd.log. I luckily found a solution in quite a short time. The problem was that the shibd was trying to create socket in /var/run/shibboleth directory, which did not exist. Creating it once does not help because Ubuntu removes content of /var/run/ at every reboot. To fix it this has to be added to /etc/init.d/shibd

if [ ! -e /var/run/shibboleth ]
then
   mkdir /var/run/shibboleth
fi