In this video, we'll talk about managing an NTP client.
So on RHEL 10, CronyD is the default NTP service.
And you use it for the server configuration as well as
the client configuration.
And that's for the magical reason
that every NTP client by default becomes an NTP server as well.
So what do you do with it?
Well, in CronyConf, you specify the time synchronization
parameters.
And to tell it where you want to get the time from,
you include a line like pool2.rhel.pool.ntp.org.
Pool is a group of NTP servers.
And you can pick whichever you want.
iBurst is the option that does a fast synchronization
if your time is off.
Normally, you get a slow sync.
So your clock is going to run faster or slower
to get towards the real time.
But in virtual environments, slow sync
is not working very well.
And that's why we need iBurst.
So pool is for a group.
You can also synchronize with an individual option
using server followed by the name of the server.
As mentioned, iBurst is for the fast synchronization.
And after modifying the contents,
you use systemctl restart CronyD.
That will restart the CronyD service.
And then you can use CronyC sources
to verify proper synchronization.
Let me show you.
So there is etccrony.conf.
And in this etccrony.conf, you can see that it has a pool.
And you can add anything you want.
So server 192.168.29.143, for instance.
Next, after adding this configuration
or changing the configuration, you
need systemctl restart CronyD.
Because otherwise, it doesn't pick it up.
And next, you use CronyC sources.
And there you can see what is currently going on.
Now, as you can see, a group of servers
with the current synchronization status.
You can also see the IP address that I just added.
So it's trying to synchronize with it.
But it did not get any information from it yet.
Well, that makes sense because the server is unreachable.
But if ever you want to add another server,
this is how you do it.
Now, what you also see is that in these four servers,
there is one of them that advertises as a stratum 1.
Stratum 1 is the highest level of reliability.
And we have a couple of others that are stratum 2.
And normally, you want to synchronize
with the highest reliability.
So if there's a stratum 1 available,
then you synchronize with that.
And your own clock is becoming a stratum 2 server.
That's how Crony time synchronization
is normally working.