AWS Certified Solutions Architect – Professional SAP-C01 – Question293

After moving an E-Commerce website for a client from a dedicated server to AWS you have also set up auto scaling to perform health checks on the instances in your group and replace instances that fail these checks. Your client has come to you with his own health check system that he wants you to use as it has proved to be very useful prior to his site running on AWS.
What do you think would be an appropriate response to this given all that you know about auto scaling and CloudWatch?

A. It is not possible to implement your own health check system due to compatibility issues.
B. It is not possible to implement your own health check system. You need to use AWSs health check system.
C. It is possible to implement your own health check system and then send the instance's health information directly from your system to CloudWatch but only in the US East (N. Virginia) region.
D. It is possible to implement your own health check system and then send the instance's health information directly from your system to CloudWatch.

Correct Answer: D

Explanation:

Explanation: Auto Scaling periodically performs health checks on the instances in your group and replaces instances that fail these checks. By default, these health checks use the results of EC2 instance status checks to determine the health of an instance. If you use a load balancer with your Auto Scaling group, you can optionally choose to include the results of Elastic Load Balancing health checks. Auto Scaling marks an instance unhealthy if the calls to the Amazon EC2 action DescribeInstanceStatus returns any other state other than running, the system status shows impaired, or the calls to Elastic Load Balancing action DescribeInstanceHealth returns OutOfService in the instance state field. After an instance is marked unhealthy because of an Amazon EC2 or Elastic Load Balancing health check, it is scheduled for replacement. You can customize the health check conducted by your Auto Scaling group by specifying additional checks or by having your own health check system and then sending the instance’s health information directly from your system to Auto Scaling.
Reference:
http://docs.aws.amazon.com/AutoScaling/latest/DeveloperGuide/health…