[CentOS] NTP and virtual guests

We encountered a problem with respect to KVM virtual host restore and NTP. Specifically, our VM test host was shutdown by an extended power outage and when power returned all of the restored guests were immediately shutdown by ntp because the time differential between the restored systems and that of the ntpd sync servers exceeded the panic threshold.

This is not an acceptable situation so in the absence of something more elegant we are contemplating shutting down ntpd on virtual hosts and scheduling regular ntpd -q from cron instead.

Is there an alternative to this? If not then what would be a recommended scheduling interval?