we have in some room ( with no connection to internet network ) , linux redhat servers
we installed the NTP clients based on crhony service on all machines to sync to NTP server
now we want to build NTP server also based on chrony service
one issue that could on the NTP server is not correct time and date because unexpected issue , so this also will be negative situation on the ntp clients
so what are the options to build stable NTP server
NTP servers are divided in stratums, being a first stratum those servers directly connected to GPS antennas, quantum clocks and stuff like that.
Since you don't have access to the internet thus not having access to external NTP servers, you must act as a stratum 0 server, and to do that you will need some mechanism to assure the time you are providing is to be trusted.
If you only relay in your BIOS clock you won't be able to provide that so you seem to be in trouble unless you are able to connect a GPS clock (or another trustable mechanism) to your servers.
If your computers form a completely detached network, and all you want to ensure is that they are synchronized among each other, you don't need a dedicated NTP server but can instead define all participating computers as peer.
In order to achieve that, remove the server statement on all machines configured as clients before, and instead add peer directives for all machines on your detached network (you will also have to add an allow statement so that the machines can access each other). You then add peer statements on the machine previously configured as server.
Far as I recall, you can buy a stand-alone box that uses a radio signal. You can buy a watch on that system for 30 bucks, but scientific research sites, astronomers and the like use time servers based on that. Try Amazon (meant as a joke, but you never know).
You could set up a system: 30-dollar watch, webcab, and some AI to see the watch going around. Great intern project.
