Welcome.
Working on our AlmaLinux system, we can look at the last of our scheduling tools,
and that is systemd and timer units.
Now using systemd with timer units, we have much more reporting capabilities,
and this then can be used to replace many of our standard cron jobs.
Now working at our command line, I can go through and use a systemctl,
and if I go through and do list‑timers,
we can see what I mean by the idea of having way more reporting.
Let's just take a look at that first entry.
This is then for updating the DNF package cache,
so the metadata relating to what's available within our software repositories.
And we can see then that it last executed 52 minutes ago,
and it's got 1 hour, 5 minutes left before it's going to execute again.
But we can see it's due to execute at 10 past 3:00,
having last executed at 1:12:19.
So we've got a really powerful reporting system,
so we can see when tasks last run and when they're due to run again.
If I go through and just quit out of this,
if I look at installing new software,
software that needs to go through and schedule tasks,
we're going to be able to see how they interact with our timers.
So I'm going to go through and run a sudo and yum install.
We've done this before, so we know what we're doing now,
‑y, and we're putting on the sysstat.
Don't forget the two s's in the middle, the sysstat package.
The sysstat package is used to collect information about system performance,
so we can see performance over a period of time.
We need to make sure the service is up and running,
but the service is going to trigger our timers.
So if I go through now and do a sudo systemctl enable ‑‑now and sysstat,
that will have enabled our timers. It's the timers that will then go
through and execute the collection routines.
If I take a look now at my list timers,
we can see that we've got a collection timer that's due to
execute again in 3:09, and a summary timer that's due to
execute in 10 hours' time. Again,
a lot of reporting, and we can see there are many standard
software packages that make use of systemd timers,
so I don't need additional services to be running to
execute our timers. Let's say the idea of putting sysstat
on is more as a demonstration, but in itself,
it's used to collect performance information, and we collect
it every 10 minutes and then make a summary once a day of
that performance information.
If I go through then and quit out of this, if I go back and execute again,
we can see now there's just 2 minutes,
20 seconds for the collection timer to run, and we're getting now
to over 9 hours for our summary timer to run. So expect to see a lot more than systemd timers in the forthcoming future.