servers.yml

Description: >
    Oluwasegun Adesanya / Udagram Projects

Parameters:

    EnvironmentName:
        Description: An environment name that will be prefixed to resource names
        Type: String
    WebServerAMI:
      Description: The machine image to be used for web servers.
      Type: String
      Default: ami-0e472ba40eb589f49

    WebServerInstanceType:
      Description: The web server EC2 instance type to be used. 
      Type: String
      Default: t2.medium

Resources:
  LBSecGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupDescription: Allow http to our load balancer
      VpcId:
        Fn::ImportValue:
          !Sub "${EnvironmentName}-VPCID"
      SecurityGroupIngress:
      - IpProtocol: tcp
        FromPort: 80
        ToPort: 80
        CidrIp: 0.0.0.0/0
      SecurityGroupEgress:
      - IpProtocol: tcp
        FromPort: 80
        ToPort: 80
        CidrIp: 0.0.0.0/0

  WebServerSecGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupDescription: Allow http to our hosts and SSH from local only
      VpcId:
        Fn::ImportValue:
          !Sub "${EnvironmentName}-VPCID"
      SecurityGroupIngress:
      - IpProtocol: tcp
        FromPort: 8080
        ToPort: 8080
        CidrIp: 0.0.0.0/0

      - IpProtocol: tcp
        FromPort: 22
        ToPort: 22
        CidrIp: 0.0.0.0/0
      SecurityGroupEgress:
      - IpProtocol: tcp
        FromPort: 0
        ToPort: 65535
        CidrIp: 0.0.0.0/0
  WebAppLaunchConfig:
    Type: AWS::AutoScaling::LaunchConfiguration
    Properties:
      UserData:
        Fn::Base64: !Sub |
          #!/bin/bash
          sudo apt-get update -y
          sudo apt-get install apache2 -y
          sudo systemctl start apache2.service          
      ImageId: ami-0e472ba40eb589f49
      SecurityGroups:
      - Ref: WebServerSecGroup
      InstanceType: t2.medium
      BlockDeviceMappings:
      - DeviceName: "/dev/sdk"
        Ebs:
          VolumeSize: '10'
  WebAppGroup:
    Type: AWS::AutoScaling::AutoScalingGroup
    Properties:
      VPCZoneIdentifier:
      - Fn::ImportValue: 
          !Sub "${EnvironmentName}-PRIV-NETS"
      LaunchConfigurationName:
        Ref: WebAppLaunchConfig
      MinSize: '4'
      MaxSize: '6'
      TargetGroupARNs:
      - Ref: WebAppTargetGroup
  WebAppLB:
    Type: AWS::ElasticLoadBalancingV2::LoadBalancer
    Properties:
      Subnets:
      - Fn::ImportValue: !Sub "${EnvironmentName}-PUB1-SN"
      - Fn::ImportValue: !Sub "${EnvironmentName}-PUB2-SN"
      SecurityGroups:
      - Ref: LBSecGroup
  Listener:
    Type: AWS::ElasticLoadBalancingV2::Listener
    Properties:
      DefaultActions:
      - Type: forward
        TargetGroupArn:
          Ref: WebAppTargetGroup
      LoadBalancerArn:
        Ref: WebAppLB
      Port: '80'
      Protocol: HTTP
  ALBListenerRule:
      Type: AWS::ElasticLoadBalancingV2::ListenerRule
      Properties:
        Actions:
        - Type: forward
          TargetGroupArn: !Ref 'WebAppTargetGroup'
        Conditions:
        - Field: path-pattern
          Values: [/]
        ListenerArn: !Ref 'Listener'
        Priority: 1
  WebAppTargetGroup:
    Type: AWS::ElasticLoadBalancingV2::TargetGroup
    Properties:
      HealthCheckIntervalSeconds: 10
      HealthCheckPath: /
      HealthCheckProtocol: HTTP
      HealthCheckTimeoutSeconds: 8
      HealthyThresholdCount: 2
      Port: 8080
      Protocol: HTTP
      UnhealthyThresholdCount: 5
      VpcId: 
        Fn::ImportValue:
          Fn::Sub: "${EnvironmentName}-VPCID"
      
  WebServerScaleUpPolicy:
      Type: AWS::AutoScaling::ScalingPolicy
      Properties:
        AdjustmentType: ChangeInCapacity
        AutoScalingGroupName:
          Ref: WebAppGroup
        Cooldown: '60'
        ScalingAdjustment: '1'

  WebServerScaleDownPolicy:
    Type: AWS::AutoScaling::ScalingPolicy
    Properties:
      AdjustmentType: ChangeInCapacity
      AutoScalingGroupName:
        Ref: WebAppGroup
      Cooldown: '60'
      ScalingAdjustment: "-1"
  
  CPUAlarmHigh:
    Type: AWS::CloudWatch::Alarm
    Properties:
      AlarmDescription: Scale-up if CPU > 90% for 10 minutes
      MetricName: CPUUtilization
      Namespace: AWS/EC2
      Statistic: Average
      Period: '300'
      EvaluationPeriods: '2'
      Threshold: '90'
      AlarmActions:
      - Ref: WebServerScaleUpPolicy
      Dimensions:
      - Name: AutoScalingGroupName
        Value:
          Ref: WebAppGroup
      ComparisonOperator: GreaterThanThreshold

  CPUAlarmLow:
    Type: AWS::CloudWatch::Alarm
    Properties:
      AlarmDescription: Scale-down if CPU < 70% for 10 minutes
      MetricName: CPUUtilization
      Namespace: AWS/EC2
      Statistic: Average
      Period: '300'
      EvaluationPeriods: '2'
      Threshold: '70'
      AlarmActions:
      - Ref: WebServerScaleDownPolicy
      Dimensions:
      - Name: AutoScalingGroupName
        Value:
          Ref: WebAppGroup
      ComparisonOperator: LessThanThreshold

  UdagramS3ReadOnlyEC2:
    Type: 'AWS::IAM::Role'
    Properties:
      ManagedPolicyArns: 
        - "arn:aws:iam::aws:policy/AmazonS3ReadOnlyAccess"
        - "arn:aws:iam::aws:policy/AmazonSSMFullAccess"
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
          - Effect: Allow
            Principal:
              Service:
              - ec2.amazonaws.com
            Action:
              - 'sts:AssumeRole'
      Path: "/"
  
  ProfileWithRolesForApp:
    Type: AWS::IAM::InstanceProfile
    Properties:
      Path: "/" 
      Roles: 
        - !Ref UdagramS3ReadOnlyEC2