Robuta

https://github.com/mlichvar/leapshm
SHM refclock for ntpd/chronyd to simulate leap second - mlichvar/leapshm
githubshmntpdchronydsimulate
https://www.digi.com/support/knowledge-base/description-of-chronyd-operation-and-ntp-sample-fr
sample frequencydescriptionchronydoperationntp