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Difficulty: MediumRoute 53 DNS Failover

A SysOps administrator needs to configure active-passive DNS failover for a public-facing API. The primary endpoint is hosted in an on-premises datacenter, and the secondary disaster recovery endpoint is hosted on an Amazon EC2 instance in AWS. If the on-premises endpoint becomes unreachable, Route 53 must automatically redirect traffic to the EC2 instance. How should the administrator configure Amazon Route 53 to meet these requirements?

  1. Configure a Route 53 health check for the on-premises endpoint. Create a primary record with a Failover routing policy pointing to the on-premises IP address and associate it with the health check. Create a secondary record with a Failover routing policy pointing to the EC2 instance IP address.Answer
  2. B
    Create weighted routing records for both endpoints, setting the weight of the primary record to 100 and the secondary record to 0, and associate a Route 53 health check with both records.
  3. C
    Configure a CloudWatch alarm using standard monitoring metrics to check on-premises health, and use a Simple routing record that automatically redirects traffic to the secondary IP when the alarm triggers.
  4. D
    Create a primary record with a Failover routing policy pointing to the on-premises IP, and configure the secondary record to point directly to an Amazon RDS Read Replica endpoint to handle application traffic during a failover.

Answer

Configure a Route 53 health check for the on-premises endpoint. Create a primary record with a Failover routing policy pointing to the on-premises IP address and associate it with the health check. Create a secondary record with a Failover routing policy pointing to the EC2 instance IP address.
The correct configuration is to configure a Route 53 health check for the on-premises endpoint, then create a primary record with a Failover routing policy pointing to the on-premises IP address and associate it with the health check, and finally create a secondary record with a Failover routing policy pointing to the EC2 instance IP address. This properly defines an active-passive failover configuration where DNS queries resolve to the primary endpoint until the associated health check fails, at which point Route 53 begins responding with the secondary endpoint IP address.

Step-by-Step Solution

1
Create a Route 53 health check that monitors the IP address or domain name of the primary on-premises API endpoint.
Amazon Route 53 will begin actively probing the on-premises endpoint to determine its health status.
Route 53 requires a health check to monitor the primary record's health state before it can execute an automated failover.
2
Create the primary DNS record in the hosted zone using the Failover routing policy, point it to the on-premises IP, and associate it with the created health check.
A primary failover record is established with an active monitor.
This establishes the default path for client traffic under normal operating conditions.
3
Create the secondary DNS record with the same record name, select the Failover routing policy, configure it as the secondary record, and point it to the EC2 instance's public IP address.
A secondary failover record is created.
This provides a backup destination for DNS queries when Route 53 detects that the primary endpoint is unhealthy.

Key Concept

Route 53 active-passive DNS failover requires a primary record with a health check and a secondary record, both configured with the Failover routing policy.
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Topics

Route 53 DNS Failover

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