[libvirt-users] libvirtd audit log

Hi I according to libvirt.org Audit log guide ,I install auditd in my system(ubuntu 16.04.2), but when I operate guest running in host, I can't not find guest audit log in /var/log/audit/audit.log, audit_level=1. when I change audit_level=2, I restart libvirtd, libvirtd start failed. Thanks