server.yml

Description: >
    Sprinceana Mihai / Udacity ND - Project 2

Parameters:

    EnvironmentName:
      Description: An environment name that will be prefixed to resource names
      Type: String

    InstanceType:
      Description: WebApp EC2 instance type
      Type: String
      Default: t2.medium
      AllowedValues: [t1.micro, t2.nano, t2.micro, t2.small, t2.medium, t2.large, m1.small,
        m1.medium, m1.large, m1.xlarge, m2.xlarge, m2.2xlarge, m2.4xlarge, m3.medium,
        m3.large, m3.xlarge, m3.2xlarge, m4.large, m4.xlarge, m4.2xlarge, m4.4xlarge,
        m4.10xlarge, c1.medium, c1.xlarge, c3.large, c3.xlarge, c3.2xlarge, c3.4xlarge,
        c3.8xlarge, c4.large, c4.xlarge, c4.2xlarge, c4.4xlarge, c4.8xlarge, g2.2xlarge,
        g2.8xlarge, r3.large, r3.xlarge, r3.2xlarge, r3.4xlarge, r3.8xlarge, i2.xlarge,
        i2.2xlarge, i2.4xlarge, i2.8xlarge, d2.xlarge, d2.2xlarge, d2.4xlarge, d2.8xlarge,
        hi1.4xlarge, hs1.8xlarge, cr1.8xlarge, cc2.8xlarge, cg1.4xlarge]
      ConstraintDescription: must be a valid EC2 instance type.

    CloudDevOpsS3Bucket:
      Description: The bucket where the code is available to download
      Type: String

    OperatorEmail:
      Description: Email address to notify if there are any scaling operations
      Type: String
      AllowedPattern: ([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)
      ConstraintDescription: must be a valid email address.

Resources:
  NotificationTopic:
    Type: AWS::SNS::Topic
    Properties:
      Subscription:
      - Endpoint: !Ref 'OperatorEmail'
        Protocol: email
  LBSecGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupDescription: Allow http to our load balancer
      VpcId:
        Fn::ImportValue:
          !Sub "${EnvironmentName}-VPCID"
      SecurityGroupIngress:
      - IpProtocol: tcp
        FromPort: 80
        ToPort: 80
        CidrIp: 0.0.0.0/0
      SecurityGroupEgress:
      - IpProtocol: tcp
        FromPort: 80
        ToPort: 80
        CidrIp: 0.0.0.0/0
  WebServerSecGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupDescription: Allow http to our hosts
      VpcId:
        Fn::ImportValue:
          !Sub "${EnvironmentName}-VPCID"
      SecurityGroupIngress:
      - IpProtocol: tcp
        FromPort: 80
        ToPort: 80
        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
          apt-get update -y
          apt-get install unzip awscli -y
          apt-get install apache2 -y
          systemctl start apache2.service
          cd /var/www/html
          aws s3 cp s3://${CloudDevOpsS3Bucket}/udacity.zip .
          unzip -o udacity.zip
          rm udacity.zip
      ImageId: ami-006a0174c6c25ac06
      SecurityGroups: [!Ref 'WebServerSecGroup']
      InstanceType: !Ref 'InstanceType'
      IamInstanceProfile: !Ref 'WebAppInstanceProfile'
      BlockDeviceMappings:
      - DeviceName: "/dev/sdk"
        Ebs:
          VolumeSize: '11'
  WebAppInstanceProfile:
    Type: AWS::IAM::InstanceProfile
    Properties:
      Roles: [!Ref 'RootRole']
  RootRole:
    Type: AWS::IAM::Role
    Properties:
      Path: /
      AssumeRolePolicyDocument:
        Statement:
        - Effect: Allow
          Principal:
            Service:
            - ec2.amazonaws.com
          Action:
          - sts:AssumeRole
  ReadAccessS3BucketsPolicy:
    Type: AWS::IAM::Policy
    Properties:
      PolicyName: download-artifacts-from-s3
      PolicyDocument:
        Statement:
        - Effect: Allow
          Action:
          - s3:GetObject
          Resource:
          - !Sub 'arn:aws:s3:::${CloudDevOpsS3Bucket}/*'
      Roles:
      - !Ref 'RootRole'

  WebAppGroup:
    Type: AWS::AutoScaling::AutoScalingGroup
    Properties:
      VPCZoneIdentifier:
      - Fn::ImportValue: !Sub "${EnvironmentName}-PRIV-NETS"
      LaunchConfigurationName: 
        Ref: WebAppLaunchConfig
      MinSize: '4'
      MaxSize: '6'
      NotificationConfigurations:
        - TopicARN: !Ref 'NotificationTopic'
          NotificationTypes: ['autoscaling:EC2_INSTANCE_LAUNCH', 'autoscaling:EC2_INSTANCE_LAUNCH_ERROR',
            'autoscaling:EC2_INSTANCE_TERMINATE', 'autoscaling:EC2_INSTANCE_TERMINATE_ERROR']
      TargetGroupARNs: [!Ref 'WebAppTargetGroup']
  WebAppScaleUpPolicy:
    Type: AWS::AutoScaling::ScalingPolicy
    Properties:
      AdjustmentType: ChangeInCapacity
      AutoScalingGroupName: !Ref 'WebAppGroup'
      Cooldown: '60'
      ScalingAdjustment: 1
  WebAppScaleDownPolicy:
    Type: AWS::AutoScaling::ScalingPolicy
    Properties:
      AdjustmentType: ChangeInCapacity
      AutoScalingGroupName: !Ref 'WebAppGroup'
      Cooldown: '60'
      ScalingAdjustment: -1
  CPUAlarmHigh:
    Type: AWS::CloudWatch::Alarm
    Properties:
      AlarmDescription: Scale-up if CPU > 90% for 10 minutes
      MetricName: CPUUtilization
      Namespace: AWS/EC2
      Statistic: Average
      Period: 300
      EvaluationPeriods: 2
      Threshold: 90
      AlarmActions: [!Ref 'WebAppScaleUpPolicy']
      Dimensions:
      - Name: AutoScalingGroupName
        Value: !Ref 'WebAppGroup'
      ComparisonOperator: GreaterThanThreshold
  CPUAlarmLow:
    Type: AWS::CloudWatch::Alarm
    Properties:
      AlarmDescription: Scale-down if CPU < 70% for 10 minutes
      MetricName: CPUUtilization
      Namespace: AWS/EC2
      Statistic: Average
      Period: 300
      EvaluationPeriods: 2
      Threshold: 70
      AlarmActions: [!Ref 'WebAppScaleDownPolicy']
      Dimensions:
      - Name: AutoScalingGroupName
        Value: !Ref 'WebAppGroup'
      ComparisonOperator: LessThanThreshold
  WebAppLB:
    Type: AWS::ElasticLoadBalancingV2::LoadBalancer
    Properties:
      Subnets:
      - Fn::ImportValue: !Sub "${EnvironmentName}-PUB1-SN"
      - Fn::ImportValue: !Sub "${EnvironmentName}-PUB2-SN"
      SecurityGroups: [!Ref 'LBSecGroup']
  Listener:
    Type: AWS::ElasticLoadBalancingV2::Listener
    Properties:
      DefaultActions:
      - Type: forward
        TargetGroupArn: !Ref 'WebAppTargetGroup'
      LoadBalancerArn: !Ref 'WebAppLB'
      Port: '80'
      Protocol: HTTP
  ALBListenerRule:
      Type: AWS::ElasticLoadBalancingV2::ListenerRule
      Properties:
        Actions:
        - Type: forward
          TargetGroupArn: !Ref 'WebAppTargetGroup'
        Conditions:
        - Field: path-pattern
          Values: [/]
        ListenerArn: !Ref 'Listener'
        Priority: 1
  WebAppTargetGroup:
    Type: AWS::ElasticLoadBalancingV2::TargetGroup
    Properties:
      HealthCheckIntervalSeconds: 10
      HealthCheckPath: /
      HealthCheckProtocol: HTTP
      HealthCheckTimeoutSeconds: 8
      HealthyThresholdCount: 2
      Port: 80
      Protocol: HTTP
      UnhealthyThresholdCount: 5
      VpcId: 
        Fn::ImportValue:
          Fn::Sub: "${EnvironmentName}-VPCID"

Outputs: 
  PublicUrl:
    Description: Public url to access the webapps
    Value: !Join ['', ['http://', !GetAtt [WebAppLB, DNSName]]]
    Export:
        Name: !Sub "${EnvironmentName}-PublicUrl"