Virtual machines wont start after update

I've just updated my SL 6 box and after reboot when i try to start the VMs I get this error

error: cannot send monitor command '{"execute":"qmp_capabilities"}': Connection reset by peer

and the /var/log/messages has the following lines

Oct 12 20:12:16 pingu libvirtd: 20:12:16.874: 1883: warning : qemudStartVMDaemon:3336 : Executing /usr/libexec/qemu-kvm
Oct 12 20:12:16 pingu libvirtd: 20:12:16.889: 1883: warning : qemudStartVMDaemon:3346 : Executing done /usr/libexec/qemu-kvm
Oct 12 20:12:16 pingu NetworkManager[1588]: <warn> /sys/devices/virtual/net/vnet0: couldn't determine device driver; ignoring...
Oct 12 20:12:17 pingu qemu-kvm: Could not find keytab file: /etc/qemu/krb5.tab: No such file or directory
Oct 12 20:12:17 pingu libvirtd: 20:12:17.432: 1883: error : qemuMonitorJSONCommandWithFd:243 : cannot send monitor command '{"execute":"qmp_capabilities"}': Connection reset by peer
Oct 12 20:12:17 pingu libvirtd: 20:12:17.433: 1878: error : virCgroupRemoveRecursively:679 : Unable to remove /cgroup/cpu/libvirt/qemu/server1/ (16)
Oct 12 20:12:17 pingu libvirtd: 20:12:17.433: 1878: error : virCgroupRemoveRecursively:679 : Unable to remove /cgroup/cpuacct/libvirt/qemu/server1/ (16)
Oct 12 20:12:17 pingu libvirtd: 20:12:17.433: 1878: error : virCgroupRemoveRecursively:679 : Unable to remove /cgroup/cpuset/libvirt/qemu/server1/ (16)
Oct 12 20:12:17 pingu libvirtd: 20:12:17.433: 1878: error : virCgroupRemoveRecursively:679 : Unable to remove /cgroup/memory/libvirt/qemu/server1/ (16)
Oct 12 20:12:17 pingu libvirtd: 20:12:17.434: 1878: error : virCgroupRemoveRecursively:679 : Unable to remove /cgroup/devices/libvirt/qemu/server1/ (16)
Oct 12 20:12:17 pingu libvirtd: 20:12:17.434: 1878: error : virCgroupRemoveRecursively:679 : Unable to remove /cgroup/freezer/libvirt/qemu/server1/ (16)
Oct 12 20:12:17 pingu libvirtd: 20:12:17.434: 1878: error : virCgroupRemoveRecursively:679 : Unable to remove /cgroup/blkio/libvirt/qemu/server1/ (16)
Oct 12 20:12:17 pingu kernel: virbr0: port 2(vnet0) entering disabled state
Oct 12 20:12:17 pingu kernel: libfcoe_device_notification: NETDEV_UNREGISTER vnet0
Oct 12 20:12:17 pingu kernel: device vnet0 left promiscuous mode
Oct 12 20:12:17 pingu kernel: virbr0: port 2(vnet0) entering disabled state


When i use the virt-manager i get this

Traceback (most recent call last):
File "/usr/share/virt-manager/virtManager/engine.py", line 878, in run_domain
vm.startup()
File "/usr/share/virt-manager/virtManager/domain.py", line 1313, in startup
self._backend.create()
File "/usr/lib64/python2.6/site-packages/libvirt.py", line 325, in create
if ret == -1: raise libvirtError ('virDomainCreate() failed', dom=self)
libvirtError: cannot send monitor command '{"execute":"qmp_capabilities"}': Connection reset by peer



I've disabled SELINUX, I've reinstalled libvirtd, tried the older kernels nothing works. I never changed anything to the machine except update. The same configuration is running since march.
Anybody got a hint ?

Thks

Does this message have anything to do with your VNC setup?

A similar error message is shown at the end of the following wiki page:

http://wiki.libvirt.org/page/VNCTLSSetup#You_receive_an_error_about_not_being_able_to_send_a_monitor_command

jk

Hi,
i'm not sure why this happend, it complains about network virt. interfaces.
Check your network setting. Do you use bridged access for your VMs? If so, the NetworkManager has to be disabled.

if nothing helps, you might try to downgrade kvm packages to older version:

cheers,

Bad snapshot from the previous shutdown. When i tried to delete the snapshot he doesnt appear in the list of snapshots. My guess is that the snapshot was not finished but the machine tried to restore from it. I've recreated the machine and now it works. I dont know why i missed this the first time (i also checked http://wiki.libvirt.org/page/VNCTLSSetup#You_receive_an_error_about_not_being_able_to_send_a_monitor_command)
My bad
THks

i'm glad you solved it and thanks for sharin the solution, i'm sure someone other will appreciate this ..

cheers