Building EC2 structure and security [closed]

Question

Is the below Amazon server architecture appropriate for a web application? What is the best way to devise an appropriate AWS architecture?

Deploying 2 instances hosting a web application (PHP application sitting on an Apache server), in 2 availability zones with both instances in a scaling group, the database on its own instance (MySQL DB) which is replicated as a standby in the second availability zone. From this point bench test the application to decide on the appropriate instances.

I have read up on best practices but with regards to security for AMI's but is the following standard or is more required:

1. System hardening - using bastille (I am guessing this will be an involved process)?
2. Intrusion detection system - Again i am new to this but I am thinking of using OSSEC?
3. IP Tables - is this over kill if you use a security group for you load balancer and for each instance type (i.e. web application instance and DB instance)?
4. Is there a need to encrypt the file system of an EC2 instance given the architecture above?
5. If not when should you encrypt a file system on EC2?

Answer 1

There are many organizations using AWS for deployments similar to the very brief requirement you mention, but the task of defining an architecture is likely to be too large to be handled in one question on SF. A good place to start getting ideas for deployment is the AWS Architecture Center, which has a number of case studies, reference architectures, and guidance on best practice.