You have been asked to de-risk deployments at your company. Specifically, the CEO is concerned about outages that occur because of accidental inconsistencies between Staging and Production, which sometimes cause unexpected behaviors in Production even when Staging tests pass. You already use Docker to get high consistency between Staging and Production for the application environment on your EC2 instances. How do you further de-risk the rest of the execution environment, since, in AWS, there are many service components you may use beyond EC2 virtual machines?

Answer options:

A.Develop models of your entire cloud system in CloudFormation. Use this model in Staging and Production to achieve greater parity.
B.Use AWS Config to force the Staging and Production stacks to have configuration parity. Any differences will be detected for you, so you are aware of risks.
C.Use AMIs to ensure the whole machine, including the kernel of the virtual machines, is consistent since Docker uses Linux Container (LXC) technology. We need to make sure the container environment is consistent.
D.Use AWS ECS and Docker clustering. This will make sure that the AMIs and machine sizes are the same across both environments.

Answer – A
After you have your stacks and resources set up, you can reuse your templates to replicate your infrastructure in multiple environments. For example, you can create environments for development, testing, and production so that you can test changes before implementing them into production. To make templates reusable, use the parameters, mappings, and conditions sections so that you can customize your stacks when you create them. For example, for your development environments, you can specify a lower-cost instance type compared to your production environment, but all other configurations and settings remain the same.
For more information on Cloudformation best practices, please refer to the below link:
http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/best-practices.html