[libvirt] libvirt-libxl driver defaulting to tap disk and not working (on Fedora 18 and rawhide)

Hi Jim, Everyone, I'm having some issues when trying out libvirt-libxl driver on my Fedora, bot on Fedora 18 and Fedorra rawhide (the former seems to be running 0.10.2.3, the later 1.0.2). Here's what happen: [root@localhost ~]# systemctl status xend.service xend.service - Xend - interface between hypervisor and some applications Loaded: loaded (/usr/lib/systemd/system/xend.service; disabled) Active: inactive (dead) [root@localhost ~]# virt-install -l http://fedora.mirror.constant.com/linux/releases/18/Fedora/x86_64/os/ --ram 1024 --disk /dev/vms/F18_x64 --name F18_x64 Starting install... Retrieving file .treeinfo... | 2.2 kB 00:00 !!! Retrieving file vmlinuz... | 9.3 MB 00:06 !!! Retrieving file initrd.img... | 53 MB 00:33 !!! ERROR internal error libxenlight failed to create new domain 'F18_x64' Domain installation does not appear to have been successful. If it was, you can restart your domain by running: virsh --connect xen:/// start F18_x64 otherwise, please restart your installation. [root@localhost ~]# cat /var/log/libvirt/libxl/libxl.log ... libxl: verbose: libxl_create.c:158:libxl__domain_build_info_setdefault: qemu-xen is unavailable, use qemu-xen-traditional instead: No such file or directory libxl: debug: libxl_create.c:1174:do_domain_create: ao 0x7f566c008d90: create: how=(nil) callback=(nil) poller=0x7f566c009030 libxl: debug: libxl_device.c:229:libxl__device_disk_set_backend: Disk vdev=xvda spec.backend=tap libxl: debug: libxl_device.c:184:disk_try_backend: Disk vdev=xvda, backend tap unsuitable because blktap not available libxl: error: libxl_device.c:269:libxl__device_disk_set_backend: no suitable backend for disk xvda libxl: debug: libxl_event.c:1499:libxl__ao_complete: ao 0x7f566c008d90: complete, rc=-3 libxl: debug: libxl_create.c:1187:do_domain_create: ao 0x7f566c008d90: inprogress: poller=0x7f566c009030, flags=ic libxl: debug: libxl_event.c:1471:libxl__ao__destroy: ao 0x7f566c008d90: destroy So, it looks like it tries to use blktap, even if I'm using an LVM volume, and fails. If I go for this: [root@localhost ~]# virt-install -l http://fedora.mirror.constant.com/linux/releases/18/Fedora/x86_64/os/ --ram 1024 --disk /dev/vms/F18_x64,driver_name=phy --name F18_x64 --bridge virbr0 it works, but only because (or at least so it looks to me) I'm manually providing ",driver_name=phy". Also (as it could have been expected, I guess) there is no way I can get it to work with a file backed VHD. Is all this supposed to happen? I haven't had the chance to try out the code from git yet, do you think it would make any difference? FYI, I've also opened this Fedora bugreport, about this very same issue: https://bugzilla.redhat.com/show_bug.cgi?id=912488 Thanks and Regards, Dario -- <<This happens because I choose it to happen!>> (Raistlin Majere) ----------------------------------------------------------------- Dario Faggioli, Ph.D, http://about.me/dario.faggioli Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)