KVM guest time-keeping best practices

There are different mechanisms for time keeping. One of the best known techniques is Network Time Protocol (NTP) .This is a networking protocol for clock synchronization between computer systems over packet-switched, variable-latency data networks. One thing that needs to be considered in a virtualization environment is the maxim that the guest time should be in sync with the hypervisor/host, because it affects lots of guest operations and can cause unpredictable results if they are not in sync.

There are different ways to achieve time sync, however; it depends on the setup you have. I have seen people using NTP, setting the system clock from the hardware clock using hwclock –s and so on. The first thing that needs to be considered here is trying to make the KVM host time in sync and stable. You can use NTP-like protocols to achieve this. Once it's in place, the guest time has to be kept in sync. Even though there are different mechanisms for doing that...