You have an application consisting of a stateless web server tier running on Amazon EC2 instances behind load balancer,
and are using Amazon RDS with read replicas. Which of the following methods should you use to implement a selfhealing and cost-effective architecture? (Choose two.)
A.
Set up a third-party monitoring solution on a cluster of Amazon EC2 instances in order to emit custom CloudWatch metrics to trigger
the termination of unhealthy Amazon EC2 instances.
B.
Set up scripts on each Amazon EC2 instance to frequently send ICMP pings to the load balancer in order to determine which instance
is unhealthy and replace it.
C.
Set up an Auto Scaling group for the web server tier along with an Auto Scaling policy that uses the Amazon RDS DB CPU utilization
CloudWatch metric to scale the instances.
D.
Set up an Auto Scaling group for the web server tier along with an Auto Scaling policy that uses the Amazon EC2 CPU utilization
CloudWatch metric to scale the instances.
E.
Use a larger Amazon EC2 instance type for the web server tier and a larger DB instance type for the data storage layer to ensure that
they don’t become unhealthy.
F.
Set up an Auto Scaling group for the database tier along with an Auto Scaling policy that uses the Amazon RDS read replica lag
CloudWatch metric to scale out the Amazon RDS read replicas.
G.
Use an Amazon RDS Multi-AZ deployment.
I think D and G are the best answer.
Can anyone explain why A is correct answer.
I think A is false.
If we use AS along with ELB, AS will mark instance that unhealthy from ELB check or from AS check, and AS will replace a new one.
Hence, we no need to use third-party monitoring to handle these steps.
I agree. It should be D and G
A: Since we are looking for a cost-effective solution and if same purpose can be done by AS, we don’t need a third party monitoring.
D,G
D & G are correct answer. If G was not included int the option list then A & D could be the option
I also think D&G is the best answers.
Self healing means that is High Availability
A is wrong because setup a third-party monitoring solution that is not a cost-efficient option.
D is a solution for HA and Scalability of web server.
G is a solution for HA of RDS.
D and G
A is not cost effective
G provides sef-healing
DG
D & G too
D & G
Explanation :
G. ‘Use an Amazon RDS Multi-AZ deployment’ gives the following benifits:
Amazon RDS detects and automatically recovers from the most common failure scenarios for Multi-AZ deployments so that you can resume database operations as quickly as possible without administrative intervention. Amazon RDS automatically performs a failover in the event of any of the following:
1. Loss of availability in primary Availability Zone
2. Loss of network connectivity to primary
3. Compute unit failure on primary
4. Storage failure on primary
Ref URL : https://aws.amazon.com/rds/details/multi-az/
G is for HA(fail-over) not for self-healing. G is wrong.
D,G
I think it’s A and G.
The question is “Which of the following methods should you use to implement a selfhealing and cost-effective architecture? ”
D is for elastic scaling – not self-healing.
The only two that have anything to do with self-healing are A and G.
Auto Scaling always monitors for instance failure. In addition you may specify any metric you like for scaling, but failures are noted, terminated, and replaced, so self healing is part of Auto Scaling. D does provide this.
D & G is the correct answer