Let's talk about the last routing policy,
which is Multi-Value,
which is going to be used when you want to route traffic
to multiple resources.
And Route 53 will therefore
return multiple values or resources.
Now, you can associate them with Health Checks,
and so therefore the only resources returned
via the Multi-Value policy are going to be the ones
that are associated with a healthy Health Check.
So up to eight healthy records are going to be returned
for each Multi-Value query.
And although it looks like an ELB,
it's not a substitute for having an ELB.
The idea is that it's the client-side load balancing.
So let's look at an example.
We are going to set up multiple A Records
for our example.com,
and we associate them with Health Checks.
So when a Multi-Value query is done by our clients,
it's going to receive up to eight records back,
and then the clients will choose one of them.
But at least by combining this with Health Checks,
we know that one of the eight records being returned,
or up to eight, are going to be healthy.
And therefore the client
can have very safe queries into them.
This is going to be different, for example,
when you have a simple routing with multiple values in it,
because as you know, the simple routing policy
does not allow for Health Checks,
and therefore it's possible
that one of the resources returned in the query
of a simple routing policy will be unhealthy.
This is why Multi-Value are a little bit more powerful
as types of records.
So let's have a look in the UI at how we can test them.
So let's practice the Multi-Value record.
So let's go and create a multi-record,
so a multi dot blah blah blah.
And then the value of it
is going to be linked to us-east-1.
So I will add this value here,
and then the Routing policy is going to be Multivalue.
The Health check is going to be us-east-1.
And the Record is going to be US.
And TTL is going to be 60 seconds.
Let's add another Record.
So, multi, and again,
we're going to route to a different region,
so this one is ap-southeast-1.
So the answer is Multivalue answer.
The Health check is ap-southeast-1.
And the Record ID is going to be Asia.
And then the record TTL is one minute.
And then finally, the last one,
so again, one more Record name.
The Value is going to be linked to eu-central-1 right here.
The TTL is one minute.
And the Routing policy is Multivalue answer.
And for the Health checks,
we're going to use the one from eu-central-1.
And the Record ID is EU.
Okay, so let's create these records.
And the records are successfully created.
Now let's test it out.
So for this, we're going to use our CloudShell in here.
So let's reconnect to CloudShell.
And what I want to do is to test this record.
So I will copy the record in here,
and then I will clear my screen.
And so if I test a dig on this,
then I get three answers.
So the three IPs are returned,
and the reason is, well,
the three health checks are fully working.
So as you can see, they're all healthy.
But if I take one of them, for example,
I remove the eu-central-1,
so I'm gonna make this one unhealthy,
and I'm just going to trick it
by editing and do an Invert health status.
So this is going to make the healthy unhealthy,
and vice versa.
It's just a quick way for me
to create an unhealthy health check.
So let me pause right now.
Okay, so now my eu-central-1 health check is Unhealthy.
And so if I reissue a dig command right here,
I should expect to see only two values, yes, as a result.
So the Multivalue answer has worked,
and it worked really well.
So just to revert this, edit this health check,
and let's untick this Invert health check status,
and we're good to go.
Okay, so that's it for this lecture.
I hope you liked it.
And I will see you in the next lecture.