Currently I have a number of Ubuntu 18.04 machines on a local network without internet access configured on chrony to refer to look up to one of them as the "master" as synchronize to it. What I would also like to achieve though is that if these machines are not connected to this local network that they synchronize the time to some internet source. I need this because they will be connected to this local network only for a very limited amount of time, and I would like to keep their clocks up to date when they’re not so that they don’t drift too much. Is this something that can be achieved in chrony? What I would be looking to do is something like this:
"Master" machine: Primary clock source = internet clock, allows other machines to connect to it as slaves
Other machines: Primary clock source = Master machine, if not available revert to secondary source = internet clock