You have a web application running on six Amazon EC2 instances, consuming about 45% of
resources on each instance. You are using auto-scaling to make sure that six instances are
running at all times. The number of requests this application processes is consistent and does
not experience spikes. The application is critical to your business and you want high
availability at all times. You want the load to be distributed evenly between all instances. You
also want to use the same Amazon Machine Image (AMI) for all instances. Which of the
following architectural choices should you make?
A.
Deploy 6 EC2 instances in one availability zone and use Amazon Elastic Load Balancer.
B.
Deploy 3 EC2 instances in one region and 3 in another region and use Amazon Elastic Load
Balancer.
C.
Deploy 3 EC2 instances in one availability zone and 3 in another availability zone and use
Amazon Elastic Load Balancer.
D.
Deploy 2 EC2 instances in three regions and use Amazon Elastic Load Balancer.
Explanation:
A load balancer accepts incoming traffic from clients and routes requests to its registered EC2
instances in one or more Availability Zones.
http://docs.aws.amazon.com/ElasticLoadBalancing/latest/DeveloperGuide/how-elbworks.html
Updated Security Whitepaper link:
https://d0.awsstatic.com/whitepapers/aws-security-whitepaper.pdf
I don’t agree with the answers given here.
stating in the question that it HAS to be high available should at least implement the tier in 3 different AZ’s. if one AZ becomes unavailable, still HA is in place.
This is not the case using 2 AZ’s
Ok, but ELB can’t span across regions.
You can place two instances in 3 regions and use ELB in each region, so 3 ELB.
Then You need Route53 to distribute traffic.
You need 3 ASG as well, and You have to copy AMI between regions.
So Answer C is most accurate with given data
C looks most appropriate because for “Different region, AMI would not be available unless copied”
I can’t agree more