Resources section in AWS - Step-by-Step Execution

Process Flow - Resources section

Define Resource

↓

Specify Type & Properties

↓

CloudFormation Validates

↓

Resource Created in AWS

↓

Resource Available for Use

The Resources section defines what AWS resources to create, specifying their type and settings, then AWS creates and makes them ready.

Execution Sample

AWS

Resources:
  MyBucket:
    Type: AWS::S3::Bucket
    Properties:
      BucketName: my-example-bucket

Defines an S3 bucket named 'my-example-bucket' to be created by AWS.

Process Table

Step	Action	Resource Name	Type	Properties	Result
1	Read Resources section	MyBucket	AWS::S3::Bucket	BucketName: my-example-bucket	Resource recognized
2	Validate resource type and properties	MyBucket	AWS::S3::Bucket	BucketName: my-example-bucket	Validation successful
3	Create resource in AWS	MyBucket	AWS::S3::Bucket	BucketName: my-example-bucket	S3 bucket created
4	Resource ready	MyBucket	AWS::S3::Bucket	BucketName: my-example-bucket	Bucket available for use

💡 All resources defined are created and ready for use.

Status Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	Final
MyBucket	undefined	defined with type and properties	validated	created in AWS	ready and available

Key Moments - 2 Insights

Why must the resource type be valid in the Resources section?

Because AWS CloudFormation checks the type during validation (see execution_table step 2). An invalid type stops creation.

What happens if required properties are missing?

Validation fails at step 2 in the execution_table, so the resource is not created.

Visual Quiz - 3 Questions

Look at the execution_table, what is the result at step 3?

A S3 bucket created

B Validation successful

C Resource recognized

D Resource ready

💡 Hint

Check the 'Result' column in execution_table row with Step 3.

At which step does AWS CloudFormation validate the resource type and properties?

A Step 3

B Step 1

C Step 2

D Step 4

💡 Hint

Look at the 'Action' column in execution_table for validation.

If the Type property is missing, what would happen in the execution_table?

A Step 3 would create the bucket anyway

B Validation at step 2 would fail

C Resource recognized at step 1 would fail

D Resource ready at step 4 would be skipped

💡 Hint

Refer to key_moments about missing required properties and validation step.

Concept Snapshot

Resources section defines AWS resources to create.
Each resource has a Type and Properties.
CloudFormation validates these before creation.
Resources are created and become available.
Errors in type or properties stop deployment.

Full Transcript

The Resources section in AWS CloudFormation templates lists the resources to create. Each resource has a name, a type like AWS::S3::Bucket, and properties such as BucketName. CloudFormation reads this section, validates the resource types and properties, then creates the resources in AWS. After creation, the resources are ready to use. If the type or required properties are invalid, creation stops during validation. This process ensures your infrastructure is correctly defined and deployed.

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