Answer: B
Since the mission-critical applications require 99.999% uptime, I would need an Active-Active site replication of resources. Here one site`s failure will result in Route 53 automatically switching to the other site, thus maintaining the uptime requirement.
Option A is incorrect. Multivalve answer routing provides the ability to return multiple health-checkable IP addresses, which is a way to use DNS to improve availability and load balancing. The critical point here is that these IP addresses may not point to servers at multiple site locations. Rather they may be servers in different availability zones within the same region. Since we add a higher level of resiliency for the critical requirement, it’s always advisable to provide an entire region failure.
Option B is CORRECT. Failover routing is usually used in Disaster Recovery scenarios where an Active-Passive or Active-Active Disaster recovery configuration is required.
Option C is incorrect. A weighted routing policy is usually used to route traffic in proportions that are specified.
E.g., if there is a new version of software that needs to be tested, 20% of the traffic can be sent to that site for getting user feedback rather than sending 100% of the traffic to that site.
Option D is incorrect. A simple routing policy is used for routing traffic to a single resource, e.g., mapping an URL to a web server.
Diagram:
Reference:
https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/routing-policy.html
