How-to: Time Synchronisation for UCS in Virtual Environments
Step 1 (default)
Sync time to hypervisor at startup (enabled by default, see here)
Step 2 (default)
Enable Network Time Protocol Daemon (ntpd) on UCS (default).
The ucr variables timeserver, timeserver2, timeserver3 and timeserver4 are used as references.
Domain clients like Windows sync their time to the domain controllers (Win AD or UCS).
Disable permanent time synchronization from the hypervisor (ESXi, …) if enabled. Using time sync at boot is fine and enabled by default.
Set timeserver variables in UCS to sync to an external ntp-server (local or internet, ideally use multiple ones).
ucr set timeserver=0.de.pool.ntp.org ucr set timeserver2=1.de.pool.ntp.org ucr set timeserver3=2.de.pool.ntp.org ucr set timeserver4=3.de.pool.ntp.org systemctl restart ntpd
UCS systems by default install ntpd and synchronize to the UCS master. The mentioned ucr variables define additional servers from where they will sync time. Do NOT use UCS hosts for these variables.
Configure UCS (at least) backup servers accordingly