[libvirt] libvirt 0.6.4: Confusing error message during virDomainRestore() if network not started

Howdy, 'yall -- I found myself scratching my head for a few minutes trying to start a VM image via virDomainRestore(). Looking through the header definition in the XML, it read as follows: <interface type="network"> <mac address="00:15:3d:49:ec:0e"/> <source network="fvte-MIXED-DEFAULT"/> <target dev="vnet3"/> <model type="e1000"/> </interface> ...and on trying to do a virDomainRestore(), it exited with the following: Traceback (most recent call last): File "/usr/bin/fvte", line 8, in <module> load_entry_point('fvte==1.0', 'console_scripts', 'fvte')() File "/local/home-aux/cduffy/public_git/fvte/src/m1/fvte/cli.py", line 1838, in main cli.cmdloop() File "/opt/python25/lib/python2.5/cmd.py", line 142, in cmdloop stop = self.onecmd(line) File "/local/home-aux/cduffy/public_git/fvte/src/m1/fvte/cli.py", line 1791, in onecmd cmd.Cmd.onecmd(self, c) File "/opt/python25/lib/python2.5/cmd.py", line 219, in onecmd return func(arg) File "/local/home-aux/cduffy/public_git/fvte/src/m1/fvte/cli.py", line 1538, in do_mode self._vmm.vh_set_runmode(name, desired) File "/local/home-aux/cduffy/public_git/fvte/src/m1/fvte/vmmanip.py", line 324, in vh_set_runmode succp = (0 == virt['connect'].restore(ramfile)) File "/opt/python25/lib/python2.5/site-packages/libvirt.py", line 1224, in restore if ret == -1: raise libvirtError ('virDomainRestore() failed', conn=self) libvirt.libvirtError: internal error Failed to add tap interface 'vnet%d' to bridge 'fvtebr0' : No such device The actual issue was that the fvte-MIXED-DEFAULT network was not running, and an appropriate "virsh net-start" allowed the domain to restore correctly; detecting this condition and providing a clearer error message would probably be a Good Thing.