Problem: Ubuntu Xen System Boot Hangs After Setting System Clock Message

After installing the Ubuntu xen-server packages and rebooting the operating system using the Xen kernel the boot process appears to hang after displaying the "Setting system clock..." message.

This is a problem related to the hwclock binary which is common to a number of different Linux distributions in addition to Ubuntu.

The cleanest way to prevent this problem from occuring on an Ubuntu system is to edit the following system initialization files:

init.d/hwclockfirst.sh  
init.d/hwclock.sh

and place a exit 0 line immediately after the #!/bin/sh. For example:

#!/bin/sh
exit 0

Once this change has been made to both the hwclockfirst.sh and hwclock.sh files simply reboot the system and Ubuntu should boot fully without hanging.