[Libguestfs] cannot connect to channel device

Here is what I got. root@ubuntu:/home/john# virsh start ubuntu2 error: Failed to start domain ubuntu2 error: internal error Process exited while reading console log output: char device redirected to /dev/pts/1 bind(unix:/var/lib/libvirt/qemu/ubuntu2.libguestfs): Permission denied chardev: opening backend "socket" failed: Permission denied root@ubuntu:/home/john# ll /var/lib/libvirt/qemu/ total 20 drwxr-x--- 5 libvirt-qemu kvm  4096 Jul  5 14:44 ./ drwxr-xr-x 8 root         root 4096 May 20 04:18 ../ drwxr-xr-x 2 libvirt-qemu kvm  4096 May 20 04:18 dump/ drwxr-xr-x 2 libvirt-qemu kvm  4096 May 20 04:18 save/ drwxr-xr-x 2 libvirt-qemu kvm  4096 May 20 04:18 snapshot/ root@ubuntu:/home/john# cat /etc/libvirt/qemu/ubuntu2.xml <!-- WARNING: THIS IS AN AUTO-GENERATED FILE. CHANGES TO IT ARE LIKELY TO BE OVERWRITTEN AND LOST. Changes to this xml configuration should be made using:   virsh edit ubuntu2 or other application using the libvirt API. --> <domain type='kvm' xmlns:qemu='/schemas/domain/qemu/1.0'> <qemu:commandline>   <qemu:arg value='-s'/> </qemu:commandline>   <name>ubuntu2</name>   <uuid>03f4c36d-9509-05dd-167d-d2613d1dd883</uuid>   <memory>1024000</memory>   <currentMemory>1024000</currentMemory>   <vcpu>1</vcpu>   <os>     <type arch='x86_64' machine='pc-1.0'>hvm</type>     <boot dev='hd'/>   </os>   <features>     <acpi/>     <apic/>     <pae/>   </features>   <clock offset='utc'/>   <on_poweroff>destroy</on_poweroff>   <on_reboot>restart</on_reboot>   <on_crash>restart</on_crash>   <devices>     <emulator>/usr/bin/kvm</emulator>     <disk type='file' device='disk'>       <driver name='qemu' type='qcow2'/>       <source file='/home/john/ubuntu-1204-vm.img'/>       <target dev='hda' bus='ide'/>       <address type='drive' controller='0' bus='0' unit='0'/>     </disk>     <controller type='ide' index='0'>       <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>     </controller>     <interface type='bridge'>       <mac address='52:54:00:d4:7d:07'/>       <source bridge='br0'/>       <model type='virtio'/>       <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>     </interface>     <serial type='pty'>       <target port='0'/>     </serial>     <console type='pty'>       <target type='serial' port='0'/>     </console>     <input type='mouse' bus='ps2'/>     <graphics type='vnc' port='-1' autoport='yes'/>     <sound model='ich6'>       <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>     </sound>     <video>       <model type='cirrus' vram='9216' heads='1'/>       <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>     </video>     <memballoon model='virtio'>       <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>     </memballoon> <channel type='unix'>   <source mode='bind' path='/var/lib/libvirt/qemu/ubuntu2.libguestfs' />   <target type='virtio' name='org.libguestfs.channel.0' /> </channel>   </devices> </domain> When I deleted the <channel>...</channel> part, it will start normally. But I need it to use guestfish with --live option.