My host OS is Ubuntu Server 11.04 (natty)
After following the instructions detailed by Ubuntu's help, I created one KVM image using
sudo ubuntu-vm-builder kvm hardy --libvirt qemu:///system
The image file was created as
-rw-r--r-- 1 root root 438M 2011-06-17 14:39 ubuntu-kvm/tmpK9hbU5.qcow2
The I can list it with virsh by sudo virsh -c qemu:///system "list --all"
Id Name State ---------------------------------- - ubuntu shut off
Buth when I call
sudo virsh -c qemu:///system "start ubuntu"
The error was thrown up:
error: Failed to start domain ubuntu error: internal error process exited while connecting to monitor: kvm: -drive file=/home/myuser/vmopt/ubuntu-kvm/tmpK9hbU5.qcow2,if=none,id=drive-ide0-0-0,format=qcow2: could not open disk image /home/myuser/vmopt/ubuntu-kvm/tmpK9hbU5.qcow2: Permission denied
The user "myuser" had been added to group libvirt.
I've gone so far as to chmod the image file as well its directory to 777, but the error is still there.