udagram_servers.yml

Description: >
    Arnold Kamanzi. This script deploys ec2 instances, autscaling group, 
    security groups, load balancers and application packages for the udagram app

Parameters:

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

    ImageId:
        Description: Id of the ec2 instance
        Type: String

Resources:

  ProfileWithRolesForOurApp:
    Type: AWS::IAM::InstanceProfile
    Properties: 
      Roles:
        - Ref: UdacityS3ReadOnlyEC2
  
  UdacityS3ReadOnlyEC2:
    Type: AWS::IAM::Role
    Properties:
      RoleName: udagram-ec2-instance-role
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
          -
            Effect: Allow
            Principal:
              Service:
                - ec2.amazonaws.com
            Action:
              - sts:AssumeRole
      Path: /

  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: 80
        ToPort: 80
        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
          apt-get update -y
          apt-get install unzip awscli -y
          apt-get install apache2 -y
          systemctl start apache2.service
          cd /var/www/html
          wget https://udacity-demo-1.s3.amazonaws.com/udacity.zip
          unzip -o udacity.zip         
      ImageId: !Sub "${ImageId}"
      IamInstanceProfile: !Ref ProfileWithRolesForOurApp
      SecurityGroups:
      - Ref: WebServerSecGroup
      InstanceType: t3.medium
      BlockDeviceMappings:
      - DeviceName: "/dev/sdk"
        Ebs:
          VolumeSize: '10'

  WebAppGroup:
    Type: AWS::AutoScaling::AutoScalingGroup
    Properties:
      VPCZoneIdentifier:
      - Fn::ImportValue: 
          !Sub "${EnvironmentName}-PRIV-NETS"
      LaunchConfigurationName:
        Ref: WebAppLaunchConfig
      MinSize: '4'
      MaxSize: '5'
      TargetGroupARNs:
      - Ref: WebAppTargetGroup
  WebAppLB:
    Type: AWS::ElasticLoadBalancingV2::LoadBalancer
    Properties:
      Subnets:
      - Fn::ImportValue: !Sub "${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: 80
      Protocol: HTTP
      UnhealthyThresholdCount: 5
      VpcId: 
        Fn::ImportValue:
          Fn::Sub: "${EnvironmentName}-VPCID"

Outputs: 

    DNSName: 
        Description: A url for the load balancer
        Value: !Join [ "", [ "http://", !GetAtt WebAppLB.DNSName ]]
        Export:
          Name: !Sub ${EnvironmentName}-DNSName