levalencia AWS CloudFormation EC2 Infrastructure
Overview
Create production-ready EC2 infrastructure using AWS CloudFormation templates. This skill covers EC2 instances (On-Demand and SPOT), Security Groups, IAM roles and instance profiles, Application Load Balancers (ALB), Target Groups, template structure best practices, parameter patterns, and cross-stack references for modular, reusable infrastructure as code.
When to Use
Use this skill when:
- Creating new EC2 instances (On-Demand or SPOT)
- Configuring Security Groups for network access control
- Creating IAM roles and instance profiles for EC2
- Setting up Application Load Balancers (ALB) with target groups
- Implementing template Parameters with AWS-specific types
- Creating Outputs for cross-stack references
- Organizing templates with Mappings and Conditions
- Designing reusable, modular CloudFormation templates
Instructions
Follow these steps to create EC2 infrastructure with CloudFormation:
- Define Instance Parameters: Specify instance type, AMI ID, and key pair
- Configure Security Groups: Create rules for inbound/outbound traffic
- Set Up IAM Roles: Define instance profile for AWS access
- Add Storage: Configure EBS volumes and mount points
- Implement User Data: Add bootstrap scripts for initialization
- Configure Monitoring: Enable detailed monitoring if needed
- Add ALB Integration: Set up load balancer and target groups
- Use Spot Instances: Configure for cost optimization
For complete examples, see the EXAMPLES.md file.
Examples
The following examples demonstrate common EC2 patterns:
Example 1: EC2 Instance with Security Group
EC2Instance:
Type: AWS::EC2::Instance
Properties:
InstanceType: t3.micro
ImageId: !Ref AmiId
KeyName: !Ref KeyName
SecurityGroupIds:
- !Ref InstanceSecurityGroup
IamInstanceProfile: !Ref InstanceProfile
UserData:
Fn::Base64: |
#!/bin/bash
yum update -y
yum install -y httpd
systemctl start httpd
Example 2: Security Group Configuration
InstanceSecurityGroup:
Type: AWS::EC2::SecurityGroup
Properties:
GroupName: !Sub "${AWS::StackName}-sg"
GroupDescription: Security group for EC2 instance
VpcId: !Ref VpcId
SecurityGroupIngress:
- IpProtocol: tcp
FromPort: 80
ToPort: 80
CidrIp: 0.0.0.0/0
- IpProtocol: tcp
FromPort: 22
ToPort: 22
CidrIp: 10.0.0.0/16
Example 3: IAM Role for EC2
IAMRole:
Type: AWS::IAM::Role
Properties:
RoleName: !Sub "${AWS::StackName}-role"
AssumeRolePolicyDocument:
Version: "2012-10-17"
Statement:
- Effect: Allow
Principal:
Service: ec2.amazonaws.com
Action: sts:AssumeRole
ManagedPolicyArns:
- arn:aws:iam::aws:policy/AmazonSSMManagedInstanceCore
InstanceProfile:
Type: AWS::IAM::InstanceProfile
Properties:
InstanceProfileName: !Sub "${AWS::StackName}-profile"
Roles:
- !Ref IAMRole
For complete production-ready examples, see EXAMPLES.md.
Quick Start
Basic EC2 Instance with Secure Configuration
AWSTemplateFormatVersion: 2010-09-09
Description: Simple EC2 instance with secure SSH access
Parameters:
LatestAmiId:
Type: AWS::SSM::Parameter::Value<AWS::EC2::Image::Id>
Default: /aws/service/ami-amazon-linux-latest/amzn2-ami-hvm-x86_64-gp2
InstanceType:
Type: String
Default: t3.micro
AllowedValues:
- t3.micro
- t3.small
- t3.medium
KeyName:
Type: AWS::EC2::KeyPair::KeyName
Description: SSH key pair name
SshLocation:
Type: String
Description: CIDR block for SSH access
Default: 10.0.0.0/16
AllowedPattern: ^([0-9]{1,3}\.){3}[0-9]{1,3}/[0-9]{1,2}$
Resources:
InstanceSecurityGroup:
Type: AWS::EC2::SecurityGroup
Properties:
GroupDescription: Security group for EC2 instance
VpcId: !Ref VpcId
SecurityGroupIngress:
- IpProtocol: tcp
FromPort: 22
ToPort: 22
CidrIp: !Ref SshLocation
- IpProtocol: tcp
FromPort: 80
ToPort: 80
CidrIp: 0.0.0.0/0
Ec2Instance:
Type: AWS::EC2::Instance
Properties:
ImageId: !Ref LatestAmiId
InstanceType: !Ref InstanceType
KeyName: !Ref KeyName
SecurityGroupIds:
- !Ref InstanceSecurityGroup
SubnetId: !Ref SubnetId
Tags:
- Key: Name
Value: !Sub ${AWS::StackName}-instance
Outputs:
InstanceId:
Description: EC2 Instance ID
Value: !Ref Ec2Instance
PublicIp:
Description: Public IP address
Value: !GetAtt Ec2Instance.PublicIp
EC2 Instance with IAM Role
AWSTemplateFormatVersion: 2010-09-09
Description: EC2 instance with IAM role for S3 access
Resources:
# IAM Role for EC2 with least privilege permissions
Ec2Role:
Type: AWS::IAM::Role
Properties:
AssumeRolePolicyDocument:
Version: "2012-10-17"
Statement:
- Effect: Allow
Principal:
Service: ec2.amazonaws.com
Action: sts:AssumeRole
ManagedPolicyArns: []
Policies:
- PolicyName: S3WriteAccess
PolicyDocument:
Version: "2012-10-17"
Statement:
- Effect: Allow
Action:
- s3:PutObject
- s3:GetObject
Resource: !Sub "arn:aws:s3:::${S3BucketName}/*"
# Instance Profile
Ec2InstanceProfile:
Type: AWS::IAM::InstanceProfile
Properties:
Roles:
- !Ref Ec2Role
InstanceProfileName: !Sub ${AWS::StackName}-profile
# EC2 Instance
Ec2Instance:
Type: AWS::EC2::Instance
Properties:
ImageId: !Ref LatestAmiId
InstanceType: !Ref InstanceType
IamInstanceProfile: !Ref Ec2InstanceProfile
# ... other properties
Template Structure
Template Sections Overview
AWS CloudFormation templates are JSON or YAML files with specific sections. Each section serves a purpose in defining your infrastructure.
AWSTemplateFormatVersion: 2010-09-09 # Required - template version
Description: Optional description string # Optional description
# Section order matters for readability but CloudFormation accepts any order
Mappings: {} # Static configuration tables
Metadata: {} # Additional information about resources
Parameters: {} # Input values for customization
Rules: {} # Parameter validation rules
Conditions: {} # Conditional resource creation
Transform: {} # Macro processing (e.g., AWS::Serverless)
Resources: {} # AWS resources to create (REQUIRED)
Outputs: {} # Return values after stack creation
Format Version
The AWSTemplateFormatVersion identifies the template version. Current version is 2010-09-09.
AWSTemplateFormatVersion: 2010-09-09
Description: My CloudFormation Template
Description
Add a description to document the template's purpose. Must appear after the format version.
AWSTemplateFormatVersion: 2010-09-09
Description: >
This template creates an EC2 instance with a security group
and IAM role for running web applications. It includes:
- EC2 instance configuration
- Security group with HTTP/HTTPS access
- IAM role with S3 access permissions
Metadata
Use Metadata for additional information about resources or parameters.
Metadata:
AWS::CloudFormation::Interface:
ParameterGroups:
- Label:
default: EC2 Configuration
Parameters:
- InstanceType
- KeyName
- Label:
default: Network Configuration
Parameters:
- VpcId
- SubnetId
ParameterLabels:
InstanceType:
default: EC2 Instance Type
KeyName:
default: SSH Key Pair
Resources Section
The Resources section is the only required section. It defines AWS resources to provision.
Resources:
MyInstance:
Type: AWS::EC2::Instance
Properties:
ImageId: ami-0ff8a95407f89df2f
InstanceType: t3.micro
KeyName: my-key-pair
Tags:
- Key: Name
Value: !Sub ${AWS::StackName}-instance
Parameters
Parameter Types
Use AWS-specific parameter types for validation and easier selection in the console.
Parameters:
VpcId:
Type: AWS::EC2::VPC::Id
Description: Select an existing VPC
SubnetId:
Type: AWS::EC2::Subnet::Id
Description: Select a subnet
SecurityGroupIds:
Type: List<AWS::EC2::SecurityGroup::Id>
Description: Select existing security groups
InstanceType:
Type: AWS::EC2::InstanceType
Description: EC2 instance type
Default: t3.micro
AllowedValues:
- t3.micro
- t3.small
- t3.medium
- t3.large
AmiId:
Type: AWS::EC2::Image::Id
Description: Select an AMI
KeyName:
Type: AWS::EC2::KeyPair::KeyName
Description: Select an existing key pair
AlbArn:
Type: AWS::ElasticLoadBalancingV2::LoadBalancer::Arn
Description: Select an ALB
SSM Parameter Types
Reference Systems Manager parameters for dynamic values.
Parameters:
LatestAmiId:
Type: AWS::SSM::Parameter::Value<AWS::EC2::Image::Id>
Description: Latest AMI ID from SSM
Default: /aws/service/ami-amazon-linux-latest/amzn2-ami-hvm-x86_64-gp2
LatestAmiIdARM:
Type: AWS::SSM::Parameter::Value<AWS::EC2::Image::Id>
Description: Latest ARM AMI ID from SSM
Default: /aws/service/ami-amazon-linux-latest/amzn2-ami-hvm-arm64-gp2
Parameter Constraints
Add constraints to validate parameter values.
Parameters:
VpcCidr:
Type: String
Description: CIDR block for the VPC
Default: 10.0.0.0/16
AllowedPattern: ^([0-9]{1,3}\.){3}[0-9]{1,3}/[0-9]{1,2}$
ConstraintDescription: Must be a valid CIDR block (x.x.x.x/x)
InstanceCount:
Type: Number
Description: Number of instances to launch
Default: 1
MinValue: 1
MaxValue: 10
Environment:
Type: String
Description: Deployment environment
Default: development
AllowedValues:
- development
- staging
- production
ConstraintDescription: Must be development, staging, or production
VolumeSize:
Type: Number
Description: EBS volume size in GB
Default: 20
MinValue: 8
MaxValue: 1000
Mappings
Use Mappings for static configuration data based on regions or other factors.
Mappings:
RegionMap:
us-east-1:
HVM64: ami-0ff8a95407f89df2f
HVMG2: ami-0a0c776d80e2a1f3c
us-west-2:
HVM64: ami-0a0c776d80e2a1f3c
HVMG2: ami-0a0c776d80e2a1f3c
eu-west-1:
HVM64: ami-0ff8a95407f89df2f
HVMG2: ami-0a0c776d80e2a1f3c
EnvironmentConfig:
development:
InstanceType: t3.micro
MinInstances: 1
MaxInstances: 2
EnableAutoScaling: false
staging:
InstanceType: t3.small
MinInstances: 1
MaxInstances: 3
EnableAutoScaling: false
production:
InstanceType: t3.medium
MinInstances: 2
MaxInstances: 10
EnableAutoScaling: true
Resources:
Instance:
Type: AWS::EC2::Instance
Properties:
ImageId: !FindInMap [RegionMap, !Ref AWS::Region, HVM64]
InstanceType: !FindInMap [EnvironmentConfig, !Ref Environment, InstanceType]
Conditions
Use Conditions to conditionally create resources based on parameters.
Parameters:
DeployAlb:
Type: String
Default: true
AllowedValues:
- true
- false
Environment:
Type: String
Default: development
AllowedValues:
- development
- staging
- production
UseSpotInstance:
Type: String
Default: false
AllowedValues:
- true
- false
Conditions:
ShouldDeployAlb: !Equals [!Ref DeployAlb, true]
IsProduction: !Equals [!Ref Environment, production]
ShouldUseSpot: !Equals [!Ref UseSpotInstance, true]
IsNotDevelopment: !Not [!Equals [!Ref Environment, development]]
Resources:
ApplicationLoadBalancer:
Type: AWS::ElasticLoadBalancingV2::LoadBalancer
Condition: ShouldDeployAlb
Properties:
Scheme: internet-facing
SecurityGroups:
- !Ref AlbSecurityGroup
Subnets: !Ref PublicSubnetIds
ProductionScalingPolicy:
Type: AWS::AutoScaling::ScalingPolicy
Condition: IsProduction
Properties:
AutoScalingGroupName: !Ref AutoScalingGroup
PolicyType: TargetTrackingScaling
TargetTrackingConfiguration:
PredefinedMetricSpecification:
PredefinedMetricType: ASGAverageCPUUtilization
TargetValue: 70.0
Transform
Use Transform for macros like AWS::Serverless for SAM templates.
AWSTemplateFormatVersion: 2010-09-09
Transform: AWS::Serverless-2016-10-31
Description: SAM template for serverless application with EC2
Resources:
MyFunction:
Type: AWS::Serverless::Function
Properties:
Handler: index.handler
Runtime: nodejs18.x
CodeUri: function/
Outputs and Cross-Stack References
Basic Outputs
Outputs:
InstanceId:
Description: EC2 Instance ID
Value: !Ref Ec2Instance
PublicIp:
Description: Public IP address
Value: !GetAtt Ec2Instance.PublicIp
PrivateIp:
Description: Private IP address
Value: !GetAtt Ec2Instance.PrivateIp
AvailabilityZone:
Description: Availability Zone
Value: !GetAtt Ec2Instance.AvailabilityZone
Exporting Values for Cross-Stack References
Export values so other stacks can import them.
Outputs:
InstanceId:
Description: EC2 Instance ID for other stacks
Value: !Ref Ec2Instance
Export:
Name: !Sub ${AWS::StackName}-InstanceId
SecurityGroupId:
Description: Security Group ID for other stacks
Value: !Ref InstanceSecurityGroup
Export:
Name: !Sub ${AWS::StackName}-SecurityGroupId
InstanceRoleArn:
Description: IAM Role ARN for other stacks
Value: !GetAtt Ec2Role.Arn
Export:
Name: !Sub ${AWS::StackName}-InstanceRoleArn
TargetGroupArn:
Description: Target Group ARN for other stacks
Value: !Ref ApplicationTargetGroup
Export:
Name: !Sub ${AWS::StackName}-TargetGroupArn
Importing Values in Another Stack
Parameters:
VpcId:
Type: AWS::EC2::VPC::Id
Description: VPC ID from network stack
SecurityGroupId:
Type: AWS::EC2::SecurityGroup::Id
Description: Security Group ID from security stack
InstanceRoleArn:
Type: String
Description: IAM Role ARN from security stack
# Or use Fn::ImportValue for programmatic access
Resources:
SecurityGroup:
Type: AWS::EC2::SecurityGroup
Properties:
VpcId: !ImportValue
Fn::Sub: ${NetworkStackName}-VpcId
GroupDescription: Security group for application
Instance:
Type: AWS::EC2::Instance
Properties:
IamInstanceProfile: !ImportValue
Fn::Sub: ${SecurityStackName}-InstanceRoleArn
Cross-Stack Reference Pattern
Create a dedicated security stack that exports values:
# security-stack.yaml
AWSTemplateFormatVersion: 2010-09-09
Description: Security resources stack
Resources:
InstanceSecurityGroup:
Type: AWS::EC2::SecurityGroup
Properties:
GroupDescription: Security group for EC2 instances
VpcId: !Ref VpcId
SecurityGroupIngress:
- IpProtocol: tcp
FromPort: 80
ToPort: 80
CidrIp: 0.0.0.0/0
Ec2Role:
Type: AWS::IAM::Role
Properties:
AssumeRolePolicyDocument:
Version: "2012-10-17"
Statement:
- Effect: Allow
Principal:
Service: ec2.amazonaws.com
Action: sts:AssumeRole
Outputs:
SecurityGroupId:
Value: !Ref InstanceSecurityGroup
Export:
Name: !Sub ${AWS::StackName}-SecurityGroupId
InstanceRoleArn:
Value: !GetAtt Ec2Role.Arn
Export:
Name: !Sub ${AWS::StackName}-InstanceRoleArn
Application stack imports these values:
# application-stack.yaml
AWSTemplateFormatVersion: 2010-09-09
Description: Application stack that imports from security stack
Parameters:
SecurityStackName:
Type: String
Description: Name of the security stack
Default: security-stack
Resources:
Ec2Instance:
Type: AWS::EC2::Instance
Properties:
ImageId: !Ref AmiId
InstanceType: !Ref InstanceType
SecurityGroupIds:
- !ImportValue
Fn::Sub: ${SecurityStackName}-SecurityGroupId
IamInstanceProfile: !ImportValue
Fn::Sub: ${SecurityStackName}-InstanceRoleArn
EC2 Instances
Basic Instance Configuration
Resources:
Ec2Instance:
Type: AWS::EC2::Instance
Properties:
ImageId: !Ref AmiId
InstanceType: !Ref InstanceType
KeyName: !Ref KeyName
SubnetId: !Ref SubnetId
SecurityGroupIds:
- !Ref SecurityGroup
UserData:
Fn::Base64: |
#!/bin/bash
yum update -y
yum install -y httpd
systemctl start httpd
Tags:
- Key: Name
Value: !Sub ${AWS::StackName}-instance
- Key: Environment
Value: !Ref EnvironmentName
Instance with Multiple Volumes
Resources:
Ec2Instance:
Type: AWS::EC2::Instance
Properties:
ImageId: !Ref AmiId
InstanceType: !Ref InstanceType
BlockDeviceMappings:
- DeviceName: /dev/xvda
Ebs:
VolumeSize: 20
DeleteOnTermination: true
VolumeType: gp3
- DeviceName: /dev/xvdh
Ebs:
VolumeSize: 50
DeleteOnTermination: false
VolumeType: gp3
- DeviceName: /dev/xvdi
Ebs:
VolumeSize: 100
DeleteOnTermination: false
VolumeType: st1
Instance with Detailed Monitoring
Resources:
Ec2Instance:
Type: AWS::EC2::Instance
Properties:
ImageId: !Ref AmiId
InstanceType: !Ref InstanceType
Monitoring: true
Metrics:
CollectionInterval: 60
Instance with Placement
Resources:
Ec2Instance:
Type: AWS::EC2::Instance
Properties:
ImageId: !Ref AmiId
InstanceType: !Ref InstanceType
Placement:
AvailabilityZone: !Select [0, !GetAZs '']
GroupName: !Ref PlacementGroup
Tenancy: default
SPOT Instances
SPOT Fleet
AWSTemplateFormatVersion: 2010-09-09
Description: SPOT Fleet for cost-optimized instances
Parameters:
MaxPrice:
Type: Number
Default: 0.05
Description: Maximum price per instance hour
Resources:
SpotFleet:
Type: AWS::EC2::SpotFleet
Properties:
SpotFleetRequestConfigData:
TargetCapacity: 10
IamFleetRole: !GetAtt SpotFleetRole.Arn
LaunchSpecifications:
- InstanceType: t3.micro
ImageId: !Ref AmiId
SubnetId: !Ref SubnetId
WeightedCapacity: 1
- InstanceType: t3.small
ImageId: !Ref AmiId
SubnetId: !Ref SubnetId
WeightedCapacity: 2
AllocationStrategy: lowestPrice
SpotPrice: !Sub ${MaxPrice}
SpotFleetRole:
Type: AWS::IAM::Role
Properties:
AssumeRolePolicyDocument:
Version: "2012-10-17"
Statement:
- Effect: Allow
Principal:
Service: spotfleet.amazonaws.com
Action: sts:AssumeRole
Policies:
- PolicyName: SpotFleetPolicy
PolicyDocument:
Version: "2012-10-17"
Statement:
- Effect: Allow
Action:
- ec2:DescribeInstances
- ec2:DescribeImages
Resource: "*"
SPOT Instance Request
Resources:
SpotRequest:
Type: AWS::EC2::SpotFleet
Properties:
SpotFleetRequestConfigData:
TargetCapacity: 1
IamFleetRole: !GetAtt SpotFleetRole.Arn
LaunchSpecifications:
- InstanceType: t3.medium
ImageId: !Ref AmiId
SubnetId: !Ref SubnetId
KeyName: !Ref KeyName
Type: persistent
SPOT Instance with Fallback
Resources:
OnDemandInstance:
Type: AWS::EC2::Instance
Condition: IsNotSpot
Properties:
ImageId: !Ref AmiId
InstanceType: !Ref InstanceType
SpotInstance:
Type: AWS::EC2::SpotFleet
Condition: UseSpot
Properties:
SpotFleetRequestConfigData:
TargetCapacity: 1
IamFleetRole: !GetAtt SpotFleetRole.Arn
LaunchSpecifications:
- InstanceType: t3.medium
ImageId: !Ref AmiId
SubnetId: !Ref SubnetId
Security Groups
Basic Security Group
Resources:
WebSecurityGroup:
Type: AWS::EC2::SecurityGroup
Properties:
GroupDescription: Security group for web servers
VpcId: !Ref VpcId
SecurityGroupIngress:
- IpProtocol: tcp
FromPort: 80
ToPort: 80
CidrIp: 0.0.0.0/0
- IpProtocol: tcp
FromPort: 443
ToPort: 443
CidrIp: 0.0.0.0/0
- IpProtocol: tcp
FromPort: 22
ToPort: 22
CidrIp: 10.0.0.0/16
SecurityGroupEgress:
- IpProtocol: tcp
FromPort: 443
ToPort: 443
CidrIp: 0.0.0.0/0
Tags:
- Key: Name
Value: !Sub ${AWS::StackName}-web-sg
Security Group with Self Reference
Resources:
AppSecurityGroup:
Type: AWS::EC2::SecurityGroup
Properties:
GroupDescription: Security group for application
VpcId: !Ref VpcId
SecurityGroupIngress:
- IpProtocol: tcp
FromPort: 8080
ToPort: 8080
SourceSecurityGroupId: !Ref LoadBalancerSecurityGroup
Tags:
- Key: Name
Value: !Sub ${AWS::StackName}-app-sg
DatabaseSecurityGroup:
Type: AWS::EC2::SecurityGroup
Properties:
GroupDescription: Security group for database
VpcId: !Ref VpcId
SecurityGroupIngress:
- IpProtocol: tcp
FromPort: 5432
ToPort: 5432
SourceSecurityGroupId: !Ref AppSecurityGroup
Tags:
- Key: Name
Value: !Sub ${AWS::StackName}-db-sg
Security Group for ALB
Resources:
AlbSecurityGroup:
Type: AWS::EC2::SecurityGroup
Properties:
GroupDescription: Security group for Application Load Balancer
VpcId: !Ref VpcId
SecurityGroupIngress:
- IpProtocol: tcp
FromPort: 80
ToPort: 80
CidrIp: 0.0.0.0/0
- IpProtocol: tcp
FromPort: 443
ToPort: 443
CidrIp: 0.0.0.0/0
SecurityGroupEgress:
- IpProtocol: tcp
FromPort: 80
ToPort: 80
SourceSecurityGroupId: !Ref AppSecurityGroup
- IpProtocol: tcp
FromPort: 443
ToPort: 443
SourceSecurityGroupId: !Ref AppSecurityGroup
IAM Roles
EC2 IAM Role with Least Privilege
Resources:
Ec2Role:
Type: AWS::IAM::Role
Properties:
AssumeRolePolicyDocument:
Version: "2012-10-17"
Statement:
- Effect: Allow
Principal:
Service: ec2.amazonaws.com
Action: sts:AssumeRole
ManagedPolicyArns: []
Policies:
- PolicyName: S3Access
PolicyDocument:
Version: "2012-10-17"
Statement:
- Effect: Allow
Action:
- s3:GetObject
- s3:PutObject
- s3:DeleteObject
Resource: !Sub "arn:aws:s3:::${S3BucketName}/*"
- PolicyName: CloudWatchLogs
PolicyDocument:
Version: "2012-10-17"
Statement:
- Effect: Allow
Action:
- logs:CreateLogGroup
- logs:CreateLogStream
- logs:PutLogEvents
- logs:DescribeLogStreams
Resource: !Sub "arn:aws:logs:${AWS::Region}:${AWS::AccountId}:log-group:/ec2/${EnvironmentName}/*"
Ec2InstanceProfile:
Type: AWS::IAM::InstanceProfile
Properties:
Roles:
- !Ref Ec2Role
InstanceProfileName: !Sub ${AWS::StackName}-profile
Role for Systems Manager
Resources:
SsmRole:
Type: AWS::IAM::Role
Properties:
AssumeRolePolicyDocument:
Version: "2012-10-17"
Statement:
- Effect: Allow
Principal:
Service: ec2.amazonaws.com
Action: sts:AssumeRole
ManagedPolicyArns:
- arn:aws:iam::aws:policy/AmazonSSMManagedInstanceCore
Policies:
- PolicyName: S3ReadAccess
PolicyDocument:
Version: "2012-10-17"
Statement:
- Effect: Allow
Action:
- s3:GetObject
Resource: !Sub "arn:aws:s3:::${S3BucketName}/*"
Application Load Balancer (ALB)
Basic ALB
Resources:
ApplicationLoadBalancer:
Type: AWS::ElasticLoadBalancingV2::LoadBalancer
Properties:
Name: !Sub ${AWS::StackName}-alb
Scheme: internet-facing
SecurityGroups:
- !Ref AlbSecurityGroup
Subnets:
- !Ref PublicSubnet1
- !Ref PublicSubnet2
Type: application
ApplicationTargetGroup:
Type: AWS::ElasticLoadBalancingV2::TargetGroup
Properties:
Name: !Sub ${AWS::StackName}-tg
Port: 80
Protocol: HTTP
VpcId: !Ref VpcId
TargetType: instance
HealthCheckPath: /health
HealthCheckIntervalSeconds: 30
HealthCheckTimeoutSeconds: 5
HealthyThresholdCount: 2
UnhealthyThresholdCount: 3
Tags:
- Key: Name
Value: !Sub ${AWS::StackName}-tg
ApplicationListener:
Type: AWS::ElasticLoadBalancingV2::Listener
Properties:
DefaultActions:
- Type: forward
TargetGroupArn: !Ref ApplicationTargetGroup
LoadBalancerArn: !Ref ApplicationLoadBalancer
Port: 80
Protocol: HTTP
ALB with HTTPS
Resources:
ApplicationLoadBalancer:
Type: AWS::ElasticLoadBalancingV2::LoadBalancer
Properties:
Name: !Sub ${AWS::StackName}-alb
Scheme: internet-facing
SecurityGroups:
- !Ref AlbSecurityGroup
Subnets:
- !Ref PublicSubnet1
- !Ref PublicSubnet2
ApplicationTargetGroup:
Type: AWS::ElasticLoadBalancingV2::TargetGroup
Properties:
Name: !Sub ${AWS::StackName}-tg
Port: 443
Protocol: HTTPS
VpcId: !Ref VpcId
TargetType: instance
HealthCheckPath: /health
HealthCheckProtocol: HTTPS
ApplicationListener:
Type: AWS::ElasticLoadBalancingV2::Listener
Properties:
DefaultActions:
- Type: forward
TargetGroupArn: !Ref ApplicationTargetGroup
LoadBalancerArn: !Ref ApplicationLoadBalancer
Port: 443
Protocol: HTTPS
Certificates:
- CertificateArn: !Ref CertificateArn
ApplicationListenerHttpRedirect:
Type: AWS::ElasticLoadBalancingV2::Listener
Properties:
DefaultActions:
- Type: redirect
RedirectConfig:
Host: "#{host}"
Path: "/#{path}"
Port: "443"
Protocol: "HTTPS"
Query: "#{query}"
StatusCode: HTTP_301
LoadBalancerArn: !Ref ApplicationLoadBalancer
Port: 80
Protocol: HTTP
ALB with Multiple Target Groups
Resources:
ApplicationLoadBalancer:
Type: AWS::ElasticLoadBalancingV2::LoadBalancer
Properties:
Name: !Sub ${AWS::StackName}-alb
Scheme: internet-facing
SecurityGroups:
- !Ref AlbSecurityGroup
Subnets:
- !Ref PublicSubnet1
- !Ref PublicSubnet2
ApiTargetGroup:
Type: AWS::ElasticLoadBalancingV2::TargetGroup
Properties:
Name: !Sub ${AWS::StackName}-api-tg
Port: 8080
Protocol: HTTP
VpcId: !Ref VpcId
HealthCheckPath: /actuator/health
WebTargetGroup:
Type: AWS::ElasticLoadBalancingV2::TargetGroup
Properties:
Name: !Sub ${AWS::StackName}-web-tg
Port: 80
Protocol: HTTP
VpcId: !Ref VpcId
HealthCheckPath: /health
ApiListenerRule:
Type: AWS::ElasticLoadBalancingV2::ListenerRule
Properties:
Actions:
- Type: forward
TargetGroupArn: !Ref ApiTargetGroup
Conditions:
- Field: path-pattern
Values:
- /api/*
- /v1/*
ListenerArn: !Ref ApplicationListener
Priority: 10
WebListenerRule:
Type: AWS::ElasticLoadBalancingV2::ListenerRule
Properties:
Actions:
- Type: forward
TargetGroupArn: !Ref WebTargetGroup
Conditions:
- Field: path-pattern
Values:
- /*
ListenerArn: !Ref ApplicationListener
Priority: 100
ALB with Cross-Zone Load Balancing
Resources:
ApplicationLoadBalancer:
Type: AWS::ElasticLoadBalancingV2::LoadBalancer
Properties:
Name: !Sub ${AWS::StackName}-alb
Scheme: internet-facing
SecurityGroups:
- !Ref AlbSecurityGroup
Subnets:
- !Ref PublicSubnet1
- !Ref PublicSubnet2
LoadBalancerAttributes:
- Key: load_balancing.cross_zone.enabled
Value: true
Complete Example
Full EC2 Stack with ALB
AWSTemplateFormatVersion: 2010-09-09
Description: Complete EC2 stack with ALB, security groups, and IAM role
Parameters:
EnvironmentName:
Type: String
Default: production
LatestAmiId:
Type: AWS::SSM::Parameter::Value<AWS::EC2::Image::Id>
Default: /aws/service/ami-amazon-linux-latest/amzn2-ami-hvm-x86_64-gp2
InstanceType:
Type: String
Default: t3.micro
AllowedValues:
- t3.micro
- t3.small
- t3.medium
- t3.large
VpcCidr:
Type: String
Default: 10.0.0.0/16
Resources:
# VPC
VPC:
Type: AWS::EC2::VPC
Properties:
CidrBlock: !Ref VpcCidr
EnableDnsHostnames: true
EnableDnsSupport: true
Tags:
- Key: Name
Value: !Sub ${EnvironmentName}-vpc
- Key: Environment
Value: !Ref EnvironmentName
# Internet Gateway
InternetGateway:
Type: AWS::EC2::InternetGateway
Properties:
Tags:
- Key: Name
Value: !Sub ${EnvironmentName}-igw
- Key: Environment
Value: !Ref EnvironmentName
InternetGatewayAttachment:
Type: AWS::EC2::VPCGatewayAttachment
Properties:
VpcId: !Ref VPC
InternetGatewayId: !Ref InternetGateway
# Public Subnets
PublicSubnet1:
Type: AWS::EC2::Subnet
Properties:
VpcId: !Ref VPC
CidrBlock: 10.0.1.0/24
AvailabilityZone: !Select [0, !GetAZs '']
MapPublicIpOnLaunch: true
Tags:
- Key: Name
Value: !Sub ${EnvironmentName}-public-1
- Key: SubnetType
Value: Public
PublicSubnet2:
Type: AWS::EC2::Subnet
Properties:
VpcId: !Ref VPC
CidrBlock: 10.0.2.0/24
AvailabilityZone: !Select [1, !GetAZs '']
MapPublicIpOnLaunch: true
Tags:
- Key: Name
Value: !Sub ${EnvironmentName}-public-2
- Key: SubnetType
Value: Public
# Security Group for ALB
AlbSecurityGroup:
Type: AWS::EC2::SecurityGroup
Properties:
GroupDescription: Security group for ALB
VpcId: !Ref VPC
SecurityGroupIngress:
- IpProtocol: tcp
FromPort: 80
ToPort: 80
CidrIp: 0.0.0.0/0
- IpProtocol: tcp
FromPort: 443
ToPort: 443
CidrIp: 0.0.0.0/0
Tags:
- Key: Name
Value: !Sub ${EnvironmentName}-alb-sg
- Key: Environment
Value: !Ref EnvironmentName
# Security Group for EC2
InstanceSecurityGroup:
Type: AWS::EC2::SecurityGroup
Properties:
GroupDescription: Security group for EC2 instances
VpcId: !Ref VPC
SecurityGroupIngress:
- IpProtocol: tcp
FromPort: 80
ToPort: 80
SourceSecurityGroupId: !Ref AlbSecurityGroup
- IpProtocol: tcp
FromPort: 22
ToPort: 22
CidrIp: 10.0.0.0/16
Tags:
- Key: Name
Value: !Sub ${EnvironmentName}-instance-sg
- Key: Environment
Value: !Ref EnvironmentName
# IAM Role with specific permissions
Ec2Role:
Type: AWS::IAM::Role
Properties:
AssumeRolePolicyDocument:
Version: "2012-10-17"
Statement:
- Effect: Allow
Principal:
Service: ec2.amazonaws.com
Action: sts:AssumeRole
ManagedPolicyArns:
- arn:aws:iam::aws:policy/AmazonSSMManagedInstanceCore
Policies:
- PolicyName: S3Access
PolicyDocument:
Version: "2012-10-17"
Statement:
- Effect: Allow
Action:
- s3:GetObject
- s3:PutObject
Resource: !Sub "arn:aws:s3:::${S3BucketName}/*"
- PolicyName: CloudWatchLogs
PolicyDocument:
Version: "2012-10-17"
Statement:
- Effect: Allow
Action:
- logs:CreateLogGroup
- logs:CreateLogStream
- logs:PutLogEvents
Resource: !Sub "arn:aws:logs:${AWS::Region}:${AWS::AccountId}:log-group:/ec2/${EnvironmentName}/*"
Tags:
- Key: Name
Value: !Sub ${EnvironmentName}-ec2-role
Ec2InstanceProfile:
Type: AWS::IAM::InstanceProfile
Properties:
Roles:
- !Ref Ec2Role
# Application Load Balancer
ApplicationLoadBalancer:
Type: AWS::ElasticLoadBalancingV2::LoadBalancer
Properties:
Name: !Sub ${EnvironmentName}-alb
Scheme: internet-facing
SecurityGroups:
- !Ref AlbSecurityGroup
Subnets:
- !Ref PublicSubnet1
- !Ref PublicSubnet2
Type: application
ApplicationTargetGroup:
Type: AWS::ElasticLoadBalancingV2::TargetGroup
Properties:
Name: !Sub ${EnvironmentName}-tg
Port: 80
Protocol: HTTP
VpcId: !Ref VPC
TargetType: instance
HealthCheckPath: /health
HealthCheckIntervalSeconds: 30
HealthCheckTimeoutSeconds: 5
HealthyThresholdCount: 2
UnhealthyThresholdCount: 3
Tags:
- Key: Name
Value: !Sub ${EnvironmentName}-tg
ApplicationListener:
Type: AWS::ElasticLoadBalancingV2::Listener
Properties:
DefaultActions:
- Type: forward
TargetGroupArn: !Ref ApplicationTargetGroup
LoadBalancerArn: !Ref ApplicationLoadBalancer
Port: 80
Protocol: HTTP
# EC2 Instance
Ec2Instance:
Type: AWS::EC2::Instance
Properties:
ImageId: !Ref LatestAmiId
InstanceType: !Ref InstanceType
IamInstanceProfile: !Ref Ec2InstanceProfile
SecurityGroupIds:
- !Ref InstanceSecurityGroup
SubnetId: !Ref PublicSubnet1
UserData:
Fn::Base64: |
#!/bin/bash
yum update -y
yum install -y httpd
systemctl start httpd
systemctl enable httpd
echo "<h1>Hello from $(hostname)</h1>" > /var/www/html/index.html
Tags:
- Key: Name
Value: !Sub ${EnvironmentName}-instance
- Key: Environment
Value: !Ref EnvironmentName
Outputs:
InstanceId:
Description: EC2 Instance ID
Value: !Ref Ec2Instance
InstancePublicIp:
Description: EC2 Instance Public IP
Value: !GetAtt Ec2Instance.PublicIp
LoadBalancerDnsName:
Description: ALB DNS Name
Value: !GetAtt ApplicationLoadBalancer.DNSName
TargetGroupArn:
Description: Target Group ARN
Value: !Ref ApplicationTargetGroup
SecurityGroupId:
Description: Instance Security Group ID
Value: !Ref InstanceSecurityGroup
RoleArn:
Description: IAM Role ARN
Value: !GetAtt Ec2Role.Arn
Best Practices
Use AWS-Specific Parameter Types
Always use AWS-specific parameter types for validation and easier selection.
Parameters:
VpcId:
Type: AWS::EC2::VPC::Id
Description: Select a VPC
SubnetIds:
Type: List<AWS::EC2::Subnet::Id>
Description: Select subnets
SecurityGroupIds:
Type: List<AWS::EC2::SecurityGroup::Id>
Description: Select security groups
InstanceType:
Type: AWS::EC2::InstanceType
Description: EC2 instance type
KeyName:
Type: AWS::EC2::KeyPair::KeyName
Description: Select a key pair
Organize by Lifecycle
Separate resources that change at different rates into different stacks.
# Network stack - rarely changes
AWSTemplateFormatVersion: 2010-09-09
Description: Network infrastructure (VPC, subnets, routes)
Resources:
VPC: AWS::EC2::VPC
Subnets: AWS::EC2::Subnet
# Security stack - changes occasionally
AWSTemplateFormatVersion: 2010-09-09
Description: Security resources (IAM roles, security groups)
Resources:
SecurityGroups: AWS::EC2::SecurityGroup
Roles: AWS::IAM::Role
# Application stack - changes frequently
AWSTemplateFormatVersion: 2010-09-09
Description: Application resources (EC2 instances, ALB)
Parameters:
NetworkStackName:
Type: String
SecurityStackName:
Type: String
Resources:
Instances: AWS::EC2::Instance
LoadBalancer: AWS::ElasticLoadBalancingV2::LoadBalancer
Use Meaningful Names
Use AWS::StackName and parameters for consistent naming.
Resources:
Ec2Instance:
Type: AWS::EC2::Instance
Properties:
Tags:
- Key: Name
Value: !Sub ${AWS::StackName}-instance
- Key: Environment
Value: !Ref EnvironmentName
Use Pseudo Parameters
Use pseudo parameters for region-agnostic templates.
Resources:
S3Bucket:
Type: AWS::S3::Bucket
Properties:
BucketName: !Sub ${AWS::StackName}-${AWS::AccountId}-${AWS::Region}
Ec2Instance:
Type: AWS::EC2::Instance
Properties:
Tags:
- Key: StackName
Value: !Ref AWS::StackName
- Key: Region
Value: !Ref AWS::Region
Validate Before Deployment
# Validate template
aws cloudformation validate-template --template-body file://template.yaml
# Check for syntax errors
aws cloudformation validate-template \
--template-body file://template.yaml \
--query 'Description'
# Use cfn-lint for advanced validation
pip install cfn-lint
cfn-lint template.yaml
Stack Policies
Stack policies protect stack resources from unintended updates that could cause service disruption. Apply policies to prevent accidental modifications or deletions of critical resources.
Resources:
# EC2 instance - allow updates but prevent deletion
Ec2Instance:
Type: AWS::EC2::Instance
DeletionPolicy: Retain
UpdateReplacePolicy: Retain
# Database - prevent all updates
DatabaseInstance:
Type: AWS::RDS::DBInstance
DeletionPolicy: Snapshot
UpdateReplacePolicy: Retain
Stack Policy JSON Example:
{
"Statement": [
{
"Effect": "Allow",
"Action": "Update:*",
"Principal": "*",
"Resource": "*"
},
{
"Effect": "Deny",
"Action": ["Update:Delete", "Update:Replace"],
"Principal": "*",
"Resource": "LogicalId=Ec2Instance"
},
{
"Effect": "Deny",
"Action": "Update:*",
"Principal": "*",
"Resource": "LogicalId=DatabaseInstance"
}
]
}
**Apply Stack
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