Yes, I'm as well on CentOS 7.x .
It's related to PolicyKit, which crashes after many authentication checks. I would strongly recommend to disable PolicyKit support in libvirtd on RHEL/CentOS 7.x by adding following lines into /etc/libvirt/libvirtd.conf :
auth_unix_ro = "none"
auth_unix_rw = "none"
unix_sock_group = "oneadmin"
unix_sock_ro_perms = "0770"
unix_sock_rw_perms = "0770"
When PolicyKit fails, also the libvirt operations initiated by KVM IM probes or KVM VMM actions fail. OpenNebula end user then can experience random failures, which is veeery unfortunate.