We were bitten by this. I installed ntp on a running system with apt, the clock went back five minutes, thirty virtual machines crashed.
If I have a machine with a clock that's fast, that doesn't have ntp installed and can't have the clock go backwards, there's no sensible way to install ntp. -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org