Resources section in AWS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the Resources section in an AWS CloudFormation template?

The Resources section defines all the AWS resources that you want to create and manage with the template, such as EC2 instances, S3 buckets, or IAM roles.

beginner

How do you specify a resource type in the Resources section?

You specify a resource type using the 'Type' property, for example, 'AWS::S3::Bucket' to create an S3 bucket.

beginner

What is the role of the 'Properties' field inside a resource in the Resources section?

The 'Properties' field defines the settings and configuration details for the resource, like the bucket name for an S3 bucket or the instance type for an EC2 instance.

intermediate

Can the Resources section reference other resources within the same template?

Yes, resources can reference each other using intrinsic functions like !Ref or !GetAtt to connect or configure resources together.

beginner

Why is it important to define resources properly in the Resources section?

Proper definition ensures AWS creates and manages the resources correctly, avoids errors, and helps maintain infrastructure as code for easy updates and replication.

What does the 'Resources' section in a CloudFormation template contain?

A User access policies

B Output values only

C Definitions of AWS resources to create

D Template metadata

The Resources section lists all AWS resources that the template will create and manage.

Which property specifies the type of AWS resource in the Resources section?

A Type

B Name

C Properties

D ResourceId

The 'Type' property defines the AWS resource type, like AWS::EC2::Instance.

How do you configure settings for a resource in the Resources section?

A Using the Settings field

B Using the Properties field

C Using the Config field

D Using the Parameters section

The 'Properties' field contains configuration details for the resource.

Which intrinsic function is commonly used to reference another resource in the same template?

A !Ref

B !Join

C !Sub

D !FindInMap

!Ref returns the value of a resource or parameter, allowing references between resources.

What happens if a resource is not properly defined in the Resources section?

A AWS ignores the resource

B The resource is created but not managed

C The resource is created with default settings

D The stack creation fails with errors

Improper resource definitions cause stack creation or update failures.

Explain the structure and purpose of the Resources section in an AWS CloudFormation template.

Think about how you tell AWS what to build and how to set it up.

Describe how resources in the Resources section can interact or connect with each other.

Consider how one resource might need information from another.

Practice

1. What is the main purpose of the Resources section in an AWS CloudFormation template?

easy

A. To define the cloud parts AWS should create

B. To specify user permissions

C. To write code logic for the application

D. To store data in the cloud

Solution

1. Step 1: Understand the role of the Resources section

   The Resources section lists all the cloud components AWS will build, like servers or databases.

2. Step 2: Compare with other template sections

   Other sections handle permissions or outputs, but Resources is for creating cloud parts.

3. Final Answer:

   To define the cloud parts AWS should create -> Option A

4. Quick Check:

   Resources section = define cloud parts [OK]

Hint: Resources section always defines what AWS builds [OK]

Common Mistakes:

• Confusing Resources with Permissions or Outputs
• Thinking Resources stores data
• Assuming Resources runs application code

2. Which of the following is the correct way to start defining a resource named MyBucket of type AWS::S3::Bucket in the Resources section?

easy

A. "MyBucket": "AWS::S3::Bucket"

B. "Type": "AWS::S3::Bucket", "MyBucket": {}

C. "MyBucket": { "Type": "AWS::S3::Bucket" }

D. "AWS::S3::Bucket": { "MyBucket": {} }

Solution

1. Step 1: Check resource name and type syntax

   Each resource needs a unique name as key, then a block with a Type property.

2. Step 2: Match correct JSON structure

   "MyBucket": { "Type": "AWS::S3::Bucket" } correctly uses the resource name as key and sets Type inside an object.

3. Final Answer:

   "MyBucket": { "Type": "AWS::S3::Bucket" } -> Option C

4. Quick Check:

   Resource name as key + Type property = "MyBucket": { "Type": "AWS::S3::Bucket" } [OK]

Hint: Resource name is key, Type is inside its object [OK]

Common Mistakes:

• Putting Type outside resource object
• Using resource type as key instead of name
• Missing curly braces for resource details

3. Given this Resources snippet in a CloudFormation template:

{
  "MyInstance": {
    "Type": "AWS::EC2::Instance",
    "Properties": {
      "InstanceType": "t2.micro",
      "ImageId": "ami-12345678"
    }
  }
}

What will AWS create when this template is deployed?

medium

A. An EC2 instance of type t2.micro with the specified AMI

B. An S3 bucket named MyInstance

C. A Lambda function with t2.micro memory

D. A database instance with ImageId ami-12345678

Solution

1. Step 1: Identify resource type and properties

   The resource type is AWS::EC2::Instance, which creates a virtual server.

2. Step 2: Understand properties meaning

   InstanceType t2.micro means a small server; ImageId specifies the server image.

3. Final Answer:

   An EC2 instance of type t2.micro with the specified AMI -> Option A

4. Quick Check:

   EC2 instance with given type and image = An EC2 instance of type t2.micro with the specified AMI [OK]

Hint: Type AWS::EC2::Instance means a virtual server [OK]

Common Mistakes:

• Confusing EC2 with S3 or Lambda
• Ignoring Properties section
• Assuming ImageId is a database ID

4. You wrote this Resources section snippet:

{
  "MyBucket": {
    "Type": "AWS::S3::Bucket",
    "Properties": {
      "BucketName": 12345
    }
  }
}

What is the error in this configuration?

medium

A. Type AWS::S3::Bucket is invalid

B. BucketName must be a string, not a number

C. Properties section is missing

D. Resource name cannot be MyBucket

Solution

1. Step 1: Check BucketName property type

   BucketName must be text (string), but 12345 is a number here.

2. Step 2: Validate other parts

   Type and Properties exist and resource name is valid, so no error there.

3. Final Answer:

   BucketName must be a string, not a number -> Option B

4. Quick Check:

   BucketName requires string value = BucketName must be a string, not a number [OK]

Hint: BucketName must be quoted text, not a number [OK]

Common Mistakes:

• Using numbers instead of strings for names
• Misnaming resource types
• Omitting Properties section

5. You want to create two resources in your template: an S3 bucket named MyDataBucket and an EC2 instance named MyWebServer. Which Resources section snippet correctly defines both with minimal required properties?

hard

A. {
"MyDataBucket": {
"Type": "AWS::S3::Bucket",
"Properties": {
"InstanceType": "t3.micro"
}
},
"MyWebServer": {
"Type": "AWS::EC2::Instance"
}
}

B. {
"AWS::S3::Bucket": {
"MyDataBucket": {}
},
"AWS::EC2::Instance": {
"MyWebServer": {
"InstanceType": "t3.micro",
"ImageId": "ami-0abcdef1234567890"
}
}
}

C. {
"MyDataBucket": {
"Type": "AWS::EC2::Instance"
},
"MyWebServer": {
"Type": "AWS::S3::Bucket",
"Properties": {
"InstanceType": "t3.micro"
}
}
}

D. {
"MyDataBucket": {
"Type": "AWS::S3::Bucket"
},
"MyWebServer": {
"Type": "AWS::EC2::Instance",
"Properties": {
"InstanceType": "t3.micro",
"ImageId": "ami-0abcdef1234567890"
}
}
}

Solution

1. Step 1: Verify resource names and types

   MyDataBucket must be AWS::S3::Bucket, MyWebServer must be AWS::EC2::Instance.

2. Step 2: Check required properties for EC2

   EC2 instance requires InstanceType and ImageId properties; S3 bucket can be empty.

3. Step 3: Identify correct JSON structure

   { "MyDataBucket": { "Type": "AWS::S3::Bucket" }, "MyWebServer": { "Type": "AWS::EC2::Instance", "Properties": { "InstanceType": "t3.micro", "ImageId": "ami-0abcdef1234567890" } } } correctly defines both resources with proper types and properties.

4. Final Answer:

   { "MyDataBucket": { "Type": "AWS::S3::Bucket" }, "MyWebServer": { "Type": "AWS::EC2::Instance", "Properties": { "InstanceType": "t3.micro", "ImageId": "ami-0abcdef1234567890" } } } -> Option D

5. Quick Check:

   Correct types and properties for both resources = { "MyDataBucket": { "Type": "AWS::S3::Bucket" }, "MyWebServer": { "Type": "AWS::EC2::Instance", "Properties": { "InstanceType": "t3.micro", "ImageId": "ami-0abcdef1234567890" } } } [OK]

Hint: S3 needs Type only; EC2 needs Type plus InstanceType and ImageId [OK]

Common Mistakes:

• Swapping resource types
• Putting resource names inside types
• Missing required EC2 properties