Configure Site Availability with Minimum Downtime

Answer - B.

If your application is hosted on Amazon EC2 instances in multiple Amazon EC2 regions, you can reduce latency for your users by serving their requests from the Amazon EC2 region for which network latency is lowest.

Amazon Route 53 latency-based routing lets you use DNS to route user requests to the Amazon EC2 region that will give your users the fastest response.

The Evaluate Target health check will ensure availability.

If any one of the regions fails, since the evaluate target is set to true , the requests will be sent to another region.

For more information on latency based routing, please visit the link:

The correct answer is option B: Create a Route 53 Latency Based Routing Record Set that resolves to an Elastic Load Balancer in each region and has the Evaluate Target Health flag set to true.

Explanation: The given scenario consists of a website hosted on 10 EC2 instances in five regions around the globe, with two instances per region. The goal is to maintain availability with minimum downtime if one of the five regions was to lose network connectivity for an extended period.

Option A is incorrect because establishing VPN connections between instances in each region and relying on BGP to failover in the case of region-wide connectivity failure for an extended period would not be a viable solution in this scenario. BGP routing and failover are useful in maintaining connectivity between sites, but it is not designed to handle application-level failover or load balancing.

Option C is partially correct, but it is not the best solution. Creating a Route 53 Latency Based Routing Record Set that resolves to an Elastic Load Balancer in each region is a good approach to achieve low latency and high availability, but setting an appropriate health check on each Elastic Load Balancer is not enough. It is not sufficient to ensure high availability in case of region-wide connectivity failure for an extended period.

Option D is incorrect because creating an Elastic Load Balancer to place in front of the EC2 instances and setting an appropriate health check on each EL is not enough to ensure high availability in case of region-wide connectivity failure for an extended period.

Option B is the best solution because it leverages Route 53's Latency Based Routing to direct traffic to the Elastic Load Balancer in the closest region, which ensures low latency and high availability. The Evaluate Target Health flag set to true is important because it enables Route 53 to monitor the health of each Elastic Load Balancer and route traffic only to healthy instances. In case of region-wide connectivity failure for an extended period, Route 53 would automatically route traffic to the Elastic Load Balancer in a different region that is still available, ensuring high availability with minimum downtime.

In conclusion, Option B provides a reliable and scalable solution to ensure high availability and low latency for a website hosted on EC2 instances in multiple regions.