- In this video, we'll talk about system D self-healing.
I just have one demo,
but before doing the demo, a short story.
In the early days, I made good money doing consultancy.
Consultancy for high-availability clustering.
You know what that is?
In high-availability clustering
you are going to protect a vital service.
And if the vital service goes down
the highly available cluster
make sure that it's started somewhere else again.
And that's pretty important to ensure
that your services are up and running all the time.
And then came system D.
And what is system D doing?
Well system D is offering a simplified way
of high availability.
We call it self-healing.
Now the difference is that
a high availability cluster protects an entire server.
Server goes down; no worries.
Critical services are being started again
on another service.
That's something that you can't obtain
through system D self-healing.
But what you can obtain,
is that if a service is going down,
system D is starting it again automatically.
And that's all I want to show you.
(typing computer keys)
Alright, system CTL edits on HTTPD.service.
And we are going to create a service section.
And in the service section, oops, it's a typo.
In the surface section, I am including a restart, as always.
And restart sec is, well, the slide says three
then I need to be real fast.
Let's make it 10.
So restart sec is 10.
Good. Next, system CTL status on HTTPD
where we don't really see anything.
And what is going to happen
if I use kill minus nine, Of what?
Of 14.
971
That's the HTTPD process.
And I'm doing my status again.
Now what do we see?
We see active, activating, auto restart,
and this auto restart,
well, that was one second ago.
We just need to give it a little bit of time.
On the slide, you see two steps that are not
really required anymore.
Just for backward compatibility
I included them.
And that's a system CTL daemon reload.
You don't need to daemon reload,
because system D has made progress
and it picks it up automatically.
So if I do my system CTL status again, what do we see?
We see it's active and it is running.
Because the system D self-healing has helped to
repair the failing service.