AWS Certified Advanced Networking Specialty · Free Practice Question Hard
Question 5
A Network Engineer is setting up DNS failover configuration for Route 53. The engineer needs to use multiple routing policies (such as latency-based and weighted) to configure a more complex DNS failover.
Which of the following are the key points to consider while configuring a failover configuration on Route 53? (Select two)
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A
When responding to queries, Route 53 includes only the healthy primary resources in Active-active failover configuration
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B
More than half of the configured records with nonzero weights must be unhealthy before Route 53 starts to respond to DNS queries using records that have weights of zero
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C
If you're routing traffic to any AWS resources that you can create alias records for, you need to create health checks for these resources too
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D
If you're creating failover records in a private hosted zone, you must assign a public IP address to an instance in the VPC to check the health of an endpoint within a VPC by IP address
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E
Records without a health check are always considered healthy. If no record is healthy, all records are deemed to be healthy
Reveal correct answers
Correct answers: D, E
Explanation
Correct options:
Records without a health check are always considered healthy. If no record is healthy, all records are deemed to be healthy - If a record in a group of records that have the same name and type doesn't have an associated health check, Route 53 always considers it healthy and always includes it among possible responses to a query.
If none of the records in a group of records are healthy, Route 53 needs to return something in response to DNS queries, but it has no basis for choosing one record over another. In this circumstance, Route 53 considers all the records in the group to be healthy and selects one based on the routing policy and on the values that you specify for each record.
If you're creating failover records in a private hosted zone, you must assign a public IP address to an instance in the VPC to check the health of an endpoint within a VPC by IP address
If you're creating failover records in a private hosted zone, note the following:
Route 53 health checkers are outside the VPC. To check the health of an endpoint within a VPC by IP address, you must assign a public IP address to an instance in the VPC.
You can create a CloudWatch metric, associate an alarm with the metric, and then create a health check that is based on the data stream for the alarm.
Incorrect options:
If you're routing traffic to any AWS resources that you can create alias records for, you need to create health checks for these resources too - If you're routing traffic to any AWS resources that you can create alias records for, don't create health checks for those resources. When you create the alias records, you set Evaluate Target Health to Yes instead.
More than half of the configured records with nonzero weights must be unhealthy before Route 53 starts to respond to DNS queries using records that have weights of zero - All the records with non-zero weights must be unhealthy before Route 53 starts to respond to DNS queries using records that have weights of zero.
When responding to queries, Route 53 includes only the healthy primary resources for active-active failover configuration - In active-active failover, all the records that have the same name, the same type, and the same routing policy are active unless Route 53 considers them unhealthy. Route 53 can respond to a DNS query using any healthy record.
In active-passive failover, when responding to queries, Route 53 includes only the healthy primary resources. If all the primary resources are unhealthy, Route 53 begins to include only the healthy secondary resources in response to DNS queries.
References:
https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/dns-failover-types.html
Discussion
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