composite_alarm.yaml

---
AWSTemplateFormatVersion: '2010-09-09'
Description: CloudFormation Stack for EC2 Auto Scaling Group with latest Amazon Linux 2 AMI

Parameters:
  LatestAmiId:
    Description: The latest Amazon Linux 2 AMI
    Type: 'AWS::SSM::Parameter::Value<String>'
    Default: '/aws/service/ami-amazon-linux-latest/amzn2-ami-hvm-x86_64-gp2'

Resources:

  MyEC2SecurityGroup:
    Type: 'AWS::EC2::SecurityGroup'
    Properties:
      GroupDescription: EC2 Security Group for the Auto Scaling Group instances
      SecurityGroupIngress:
        - IpProtocol: tcp
          FromPort: '22'
          ToPort: '22'
          CidrIp: 0.0.0.0/0

  LaunchConfiguration:
    Type: 'AWS::AutoScaling::LaunchConfiguration'
    Properties:
      ImageId: !Ref LatestAmiId
      InstanceType: t2.micro # Choose your desired instance type
      SecurityGroups:
        - Ref: MyEC2SecurityGroup

  AutoScalingGroup:
    Type: 'AWS::AutoScaling::AutoScalingGroup'
    Properties:
      AvailabilityZones: 
        Fn::GetAZs: ''  # All available AZs in the current region
      LaunchConfigurationName: 
        Ref: LaunchConfiguration
      MinSize: '2'
      MaxSize: '20'
      DesiredCapacity: '2'
      MetricsCollection:
        - Granularity: 1Minute

  ScaleUpPolicy:
    Type: 'AWS::AutoScaling::ScalingPolicy'
    Properties:
      AutoScalingGroupName:
        Ref: AutoScalingGroup
      AdjustmentType: ChangeInCapacity
      ScalingAdjustment: '1'
      Cooldown: '300'

  HighCpuAlarm:
    Type: 'AWS::CloudWatch::Alarm'
    Properties:
      AlarmName: HighCPUUsage
      AlarmDescription: Alarm when CPU exceeds 80 percent
      Namespace: AWS/EC2
      MetricName: CPUUtilization
      Statistic: Average
      Period: '300'
      EvaluationPeriods: '1'
      Threshold: '80'
      ComparisonOperator: GreaterThanThreshold
      AlarmActions:
        - Ref: ScaleUpPolicy

  HighASGSizeAlarm:
    Type: 'AWS::CloudWatch::Alarm'
    Properties:
      AlarmName: HighASGSize
      AlarmDescription: Alarm when ASG size exceeds 10
      Namespace: AWS/AutoScaling
      MetricName: GroupTotalInstances
      Statistic: Average
      Period: '300'
      EvaluationPeriods: '1'
      Threshold: '10'
      ComparisonOperator: GreaterThanThreshold
      Dimensions:
        - Name: AutoScalingGroupName
          Value:
            Ref: AutoScalingGroup

  VeryHighCpuAlarm:
    Type: 'AWS::CloudWatch::Alarm'
    Properties:
      AlarmName: VeryHighCPUUsage
      AlarmDescription: Alarm when CPU exceeds 90 percent
      Namespace: AWS/EC2
      MetricName: CPUUtilization
      Statistic: Average
      Period: '300'
      EvaluationPeriods: '1'
      Threshold: '90'
      ComparisonOperator: GreaterThanThreshold
      Dimensions:
        - Name: AutoScalingGroupName
          Value:
            Ref: AutoScalingGroup

Outputs:
  AutoScalingGroupName:
    Description: The name of the Auto Scaling Group
    Value: 
      Ref: AutoScalingGroup