Section 5 Parameters.yml

AWSTemplateFormatVersion: "2010-09-09"
Description: A sample template

Parameters:
  MyKeyName:
    Type: AWS::EC2::KeyPair::KeyName
    Description: choose key name
  MyInstanceType:
    Type: AWS::SSM::Parameter::Value<String>
    Description: choose instance type from the list
    
  MyAZ:
    Type: String
    Description: choose A.Z from the list
    Default: us-east-2a
    AllowedValues:
      - us-east-2a
      - us-east-2b
      - us-east-2c

Resources:
  MyEC2Instance:
    Type: "AWS::EC2::Instance"
    Properties: 
      ImageId: "ami-0a0ad6b70e61be944"
      InstanceType: !Ref MyInstanceType
      KeyName: !Ref MyKeyName
      SecurityGroups:
        - !Ref MyFirstSG
      AvailabilityZone: !Ref MyAZ
  MyFirstSG:
    Type: AWS::EC2::SecurityGroup
    Properties: 
      GroupDescription: opening port 22 & 80
      SecurityGroupIngress:
        - IpProtocol: 'tcp'
          ToPort: 22
          FromPort: 22
          CidrIp: 0.0.0.0/0
        - IpProtocol: 'tcp'
          ToPort: 80
          FromPort: 80
          CidrIp: 0.0.0.0/0
  MyEIP:
    Type: AWS::EC2::EIP
    Properties:
      InstanceId: !Ref MyEC2Instance