Okay.
Hello loggers and welcome to this lecture and this lecture we're going to look at multi value and sub
policies.
Now I know what you thinking off The Last Lecture thinking.
God.
Could this get any more complicated.
The good news is is multi value answer policies are really really simple.
They're basically it's the same as simple rooting with one key difference.
So it allows you to configure Amazon Route 53 to return multiple values such as an IP address for your
web servers in response to DNS queries and you can specify multiple values for almost any record but
multi value answer rooting also allows you to check the health of each resource.
So Route 53 returns only the values for healthy resources.
So what does that mean.
Well basically this is exactly the same as simple routing.
However it allows you to put health checks on each record set.
So let's go have a look at how this works in the database console.
Okay.
So here I am in the U.S. console.
If I go over to services and I go down to Route 53 then I need to go into my hosted zones and I'm going
to click in here and we don't have any record sets in there now.
Let's go ahead and create a record set.
Now if you remember if we selected simple We pasted it in and we did it line by line.
And that was the only way using simple DNS as using simple rooting policies that were able to do it
or what we can do now is we can remove this and we can change this to simple to multi value answer.
Now the cool thing here is we can associate it with a health check.
So this is my Sydney one going to go ahead and hit Sydney.
Going to associate it with a health check and I'm going to associate this to Sydney.
So let's go ahead and hit create.
That's going to give me my first record.
Go on and create my second record set.
Now you see here it says simple and I cannot associate this with a health check.
So multi value answer allows me to add more values in so going to add in my Ohio one.
Change this to multi value answer.
And I'm going to say okay this is Ohio and I'm gonna add this to a health check which will be my Ohio
health check.
So there we go.
Now we've got our two DNS records.
So I'm gonna go back over to my browser in here and hit refresh that is connecting into Ohio right now.
Let's go over to our E2.
We'll go over to the Ohio region and what I'm gonna do is I'm going to go in and I'm actually going
to terminate the instance because we're not gonna need these instances anymore because this is the last
lecture.
So let's go in and terminate this instance he's been very good to us.
There we go.
Terminate and hit terminate.
So that is now terminating.
And what will happen is that the health check is going to start to fail with Route 53 and then Route
53 is going to remove it is no longer going to serve that record back.
So if we go over to Route 53 we're going to have to wait for about 20 seconds.
So I'm just gonna go over to my health checks I'm just going to pause the video and wait a couple of
minutes actually just to see this health check fail case I'm just gonna refresh the page and there we
go.
We have now got our Ohio one failing.
And if I go back over here and refresh and then we go it's now going over to the Irish web server.
So let's go in and we can go back to our dashboard or to our who's dead zones and we can go in and delete
that now.
Feel free to go through and delete your easy two instances we don't need them anymore.
So I'm gonna delete these records sets and you just go through and delete all your easy two instances
because you won't will not need them now.
So in terms of my exam tips just remember that multi value answer policy what's happening is the user
connects into Route 53 we're gonna have multiple records sets in there in that hosted zone they can
have health checks and if one fails their health check we're going to fail over automatically to another
IP address.
So it's basically simple rooting with health checks.
So that is it for this lecture guys are you've done very very well here at the end of the DNS section
I know DNS is not that sexy a topic and it can be a bit dry and dull.
Don't worry we're going to go on to veeps VPC is a super super fun then we're going to learn about architecture
and then we're going to learn all about Sevilla.
So we've got lots more fun to come.
So if you've got the time please join me in the next lecture.