Please attach a longer output from the log file; there are debug messages immediately before the TRACE that could be useful in identifying the problem.
I suspect the issue is that the Nova Compute domain must be running as PV, not HVM with PV tools. You can convert the domain using a guide such as http://wiki.univention.com/index.php?title=Citrix_Xen_Server#Convert_the_UCS_system_to_paravirtualization
Please attach a longer output from the log file; there are debug messages immediately before the TRACE that could be useful in identifying the problem.
I suspect the issue is that the Nova Compute domain must be running as PV, not HVM with PV tools. You can convert the domain using a guide such as http:// wiki.univention .com/index. php?title= Citrix_ Xen_Server# Convert_ the_UCS_ system_ to_paravirtuali zation