- All right.
In Linux time, time synchronization is pretty important.
So how does that work?
Well, to start with use timedatectl set-ntp
which enables or disables time synchronization.
That should be on by default.
Timedatectl timesync-status
will show you timesync-status information.
And if you want more detail
on a system that is using the chrony service
which is the case for Red Hat,
you can use chronyc sources and chronyc tracking.
For much and really, much more information
about time synchronization and the current status.
Let's go check this out.
So to start with sudo timedatectl
timesync-status
is showing us,
oh the name is not activatable.
Activatable, what does that mean?
Well, let's further investigate.
I am going to use timedatectl set,
timedatectl status,
and there we can see
NTP service: active
and system clock synchronized.
So all of that is looking good.
Now as this timedatectl
timesync status is giving some weird message.
I want to further investigate.
So sudo chrony,
chronyc sources
is what we are going to use.
And this is showing
the time sources that are actually being used.
And you know what's going on.
I think I understand what's going on.
If you use sudo systemctl
status
chrony, chronyd
then we can see that chronyd service is running.
Now it happens to be that nowadays in Linux,
there are two different services that can be used
for time synchronization.
It's either chrony or systemd-timesyncd
Systemd-timesyncd is pretty simple.
And for that reason, you won't find it always active.
And here on my Red Hat family system.
I can see chronyd service.
And that's why timedatectl timesync-status
is giving me, a service is not activatable
that's because it has been blocked out by chrony.
Chrony is doing the work and chronyc sources,
as we can see here,
is showing all the time synchronization sources,
including the stratum.
So that's a reliability, as we have just seen,
including
the offset in milliseconds,
that falls far within the 1000 seconds
limit that is allowed.
Now, if this is not enough detail
use sudo chrony,
sudo chronyc tracking.
And what is chronyc tracking giving you?
That is giving you even more detail
about the current time sync status.
For most people this is too much information.
Chronyc sources is more than enough.
It shows you the time sync sources
and it's giving you the comfortable feeling
that you are okay.
But if you need more detail, here you go.
More detail using chronyc tracking.