Parameters:
  KeyName:
    Description: Name of an existing EC2 KeyPair to enable SSH access to the instances. Linked to AWS Parameter
    Type: AWS::EC2::KeyPair::KeyName
    ConstraintDescription: must be the name of an existing EC2 KeyPair.
  InstanceType:
    Description: Enter t2.micro, t3.micro. Default is t2.micro.
    Type: String
    Default: t2.micro
    AllowedValues: 
      - t2.micro
      - t3.micro
  LatestAmiId:
    Description: (DO NOT CHANGE)
    Type: 'AWS::SSM::Parameter::Value<AWS::EC2::Image::Id>'
    Default: '/aws/service/ami-amazon-linux-latest/amzn2-ami-hvm-x86_64-gp2'
    AllowedValues:
      - /aws/service/ami-amazon-linux-latest/amzn2-ami-hvm-x86_64-gp2

Resources:
  MyVPC:
    Type: AWS::EC2::VPC
    Properties:
     CidrBlock: 10.0.0.0/16
     Tags:
        - Key: Name
          Value: ServerChk-VPC

  MyIGW:
    Type: AWS::EC2::InternetGateway
    Properties:
      Tags:
        - Key: Name
          Value: My-IGW

  MyIGWAttachment:
    Type: AWS::EC2::VPCGatewayAttachment
    Properties:
      InternetGatewayId: !Ref MyIGW
      VpcId: !Ref MyVPC

  MyPublicRT:
    Type: AWS::EC2::RouteTable
    Properties:
      VpcId: !Ref MyVPC
      Tags:
        - Key: Name
          Value: My-Public-RT

  MyDefaultPublicRoute:
    Type: AWS::EC2::Route
    DependsOn: MyIGWAttachment
    Properties:
      RouteTableId: !Ref MyPublicRT
      DestinationCidrBlock: 0.0.0.0/0
      GatewayId: !Ref MyIGW

  MyPublicSN:
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref MyVPC
      AvailabilityZone: !Select [ 0, !GetAZs '' ]
      CidrBlock: 10.0.0.0/24
      Tags:
        - Key: Name
          Value: My-Public-SN

  MyPublicSNRouteTableAssociation:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      RouteTableId: !Ref MyPublicRT
      SubnetId: !Ref MyPublicSN

  MySG:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupDescription: Enable HTTP access via port 80 and SSH access via port 22
      VpcId: !Ref MyVPC
      Tags:
        - Key: Name
          Value: My-SG
      SecurityGroupIngress:
      - IpProtocol: tcp
        FromPort: 0
        ToPort: 65535
        CidrIp: 0.0.0.0/0
      - IpProtocol: icmp
        FromPort: -1
        ToPort: -1
        CidrIp: 0.0.0.0/0

  MyEC2:
    Type: AWS::EC2::Instance
    Properties:
      InstanceType: !Ref InstanceType
      ImageId: !Ref LatestAmiId
      KeyName: !Ref KeyName
      Tags:
        - Key: Name
          Value: My-EC2
      NetworkInterfaces:
        - DeviceIndex: 0
          SubnetId: !Ref MyPublicSN
          GroupSet:
          - !Ref MySG
          AssociatePublicIpAddress: true
      UserData:
        Fn::Base64:
          !Sub |
            #!/bin/bash
            hostnamectl --static set-hostname My-EC2
            yum update -y
            amazon-linux-extras install docker -y
            systemctl start docker
            systemctl enable docker