[Users] Unable to run VM with ”opening backend ‘pyt’ failed”

Hi everyone, I installed the vdsm(4.9.6) in CentOS 6, the libvirt version is 0.9.4 and the qemu-kvm's version is 0.12.1.2. I create a VM with all default values, But, when I run the vm, it returns failure with the follow error message in WebAdmin. "internal error Process exited while reading console log output: chardev: opening backend "pty" failed. There are logs file in attachment If you want other info, please tell me. Best wishes, Xuejie Chen