AWS CloudFormation in a Nutshell

A Brief History of AWS CloudFormation

Back in 2011, AWS decided to make life easier by introducing CloudFormation, a tool that allows engineers to define AWS infrastructure in JSON (or YAML, if you have taste).

Before this, people had to:

Manually create resources through the AWS Console 😵
Write long, fragile bash scripts to automate deployments 🔧
Cry when their cloud environment wasn’t repeatable 😭

AWS CloudFormation vs. Other IaC Tools

Feature	CloudFormation	Terraform	Pulumi	Ansible
AWS-Native	✅ Yes	❌ No	❌ No	❌ No
Multi-Cloud Support	❌ No	✅ Yes	✅ Yes	✅ Yes
Language	YAML/JSON	HCL	Python/JS/Go	YAML
State Management	AWS Managed	Self-managed	Self-managed	No explicit state
Best For	AWS-only infra	Multi-cloud infra	Devs who prefer real code	Config management

If you’re all-in on AWS, CloudFormation is a solid choice.

If you need multi-cloud support, Terraform is your best bet.

Pulumi is for devs who hate YAML, and Ansible is for managing software/configurations rather than provisioning infra.

CloudFormation Code Examples

1. Create an S3 Bucket

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AWSTemplateFormatVersion: '2010-09-09'
Resources:
  MyS3Bucket:
    Type: "AWS::S3::Bucket"
    Properties:
      BucketName: "my-cloudformation-bucket"

2. Provision an EC2 Instance

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Resources:
  MyEC2Instance:
    Type: "AWS::EC2::Instance"
    Properties:
      InstanceType: "t2.micro"
      ImageId: "ami-12345678"

3. Set Up a VPC

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Resources:
  MyVPC:
    Type: "AWS::EC2::VPC"
    Properties:
      CidrBlock: "10.0.0.0/16"

4. Deploy a Load Balancer

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Resources:
  MyLoadBalancer:
    Type: "AWS::ElasticLoadBalancingV2::LoadBalancer"
    Properties:
      Name: "my-load-balancer"
      Type: "application"

5. Spin Up an RDS Database

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Resources:
  MyRDS:
    Type: "AWS::RDS::DBInstance"
    Properties:
      Engine: "mysql"
      DBInstanceClass: "db.t3.micro"
      AllocatedStorage: 20

6. Create an IAM Role

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Resources:
  MyIAMRole:
    Type: "AWS::IAM::Role"
    Properties:
      RoleName: "MyCloudFormationRole"
      AssumeRolePolicyDocument:
        Version: "2012-10-17"
        Statement:
          - Effect: "Allow"
            Principal:
              Service: "ec2.amazonaws.com"
            Action: "sts:AssumeRole"

7. Set Up an Auto Scaling Group

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Resources:
  MyAutoScalingGroup:
    Type: "AWS::AutoScaling::AutoScalingGroup"
    Properties:
      MinSize: "1"
      MaxSize: "5"

8. Deploy a Lambda Function

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Resources:
  MyLambda:
    Type: "AWS::Lambda::Function"
    Properties:
      Runtime: "python3.8"
      Handler: "index.lambda_handler"
      Code:
        S3Bucket: "my-lambda-bucket"

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Resources:
  MySNSTopic:
    Type: "AWS::SNS::Topic"
    Properties:
      DisplayName: "My SNS Topic"

10. Define a CloudWatch Alarm

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Resources:
  MyCloudWatchAlarm:
    Type: "AWS::CloudWatch::Alarm"
    Properties:
      AlarmDescription: "High CPU usage"
      ComparisonOperator: "GreaterThanThreshold"
      Threshold: 80

Key Ideas Table

Concept	Explanation
CloudFormation	AWS-native IaC tool (YAML/JSON)
State Management	AWS manages state internally
Best Use Case	Deploying AWS-only infrastructure
Comparison	Competes with Terraform, Pulumi, and Ansible
Example Uses	Provisioning VMs, databases, networks, and IAM roles