Which of the following design strategies is ideal when designing loosely coupled systems? Choose 2 answers from the options given below.

Answer options:

A.Having the web and worker roles running on the same set of EC2 Instances.
B.Having the web and worker roles running on separate EC2 Instances.
C.Using SNS to establish communication between the web and worker roles.
D.Using SQS to establish communication between the web and worker roles.

Answer – B and D
The below diagram shows the ideal design which uses SQS and separate environments for web and worker processes. The SQS queue manages the communication between the web and worker roles.
 One example is the way Elastic beanstalk manages worker environments. For more information on this, please visit the below URL:
http://docs.aws.amazon.com/elasticbeanstalk/latest/dg/using-features-managing-env-tiers.html