You are a DevOps engineer and you need to design a CloudFormation stack to manage AWS resources. You want to use the same CloudFormation template for both production and development environments. The stack includes an EC2 instance whose instance type should be c1.xlarge for production and m1.large for development. You have a Condition resource called CreateProdResources that determines whether or not the environment is production. The template uses the YAML format. How would you configure the EC2 instance type in the CloudFormation template?

Answer options:

A.EC2Instance:
Type: "AWS::EC2::Instance"
Condition: CreateProdResources
Properties:
InstanceType: !Ref [c1.xlarge, m1.large]
B.EC2Instance:
Type: "AWS::EC2::Instance"
Properties:
InstanceType: !If [CreateProdResources, c1.xlarge, m1.large] 
C.EC2Instance:
Type: "AWS::EC2::Instance"
Properties:
InstanceType: Fn::Not: [CreateProdResources, m1.large, c1.xlarge]
D.EC2Instance:
Type: "AWS::EC2::Instance"
Properties:
InstanceType: !Equals [CreateProdResources, c1.xlarge, m1.large]
 

Correct Answer – B
Option A is incorrect because the condition CreateProdResources should not be associated with the EC2 resource itself. With this configuration, the instance is created only when CreateProdResources is true.
Option B is CORRECT because the !If function returns c1.xlarge when CreateProdResources is true and m1.large when CreateProdResources is false. This is the expected result.
Option C is incorrect because Fn::Not returns true for a condition that evaluates to false or returns false for a condition that evaluates to true. It cannot return the instance type such as m1.large or c1.xlarge.
Option D is incorrect because this is not how !Equals works. !Equals is a condition that returns true if the two values are equal or false if they aren`t. This function !Equals should not be used here.
Reference:
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/intrinsic-function-reference-conditions.html,
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/conditions-sample-templates.html.