‫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.