Question about Chrony's metrics

Hi all,

I have Chrony configured with 2 sources like so:
```
server 192.168.10.1 prefer iburst
server 192.168.10.2 noselect
```
The server should be synchronized only with the first source and just
monitor the second one (hence `noselect` option).
I want to be sure that the time set on the server has no more than 1
second difference with the time obtained from both sources.

What would be the right way to do it with Chrony? What metric can be
used to check such a time drift?

Any help is very much appreciated.
Thank you!

Kind regards,
Semyon