Parameters:
  Volume:
    Description: "The size of ebs block"
    Type: String
Resources:
  MyEC2Instance:
    Type: AWS::EC2::Instance
    Properties:
      ImageId: "ami-79fd7eee"
      KeyName: "testkey"
      BlockDeviceMappings:
      - DeviceName: "/dev/sdm"
        Ebs:
          VolumeType: "io1"
          Iops: "200"
          DeleteOnTermination: "false"
          VolumeSize:
            Ref: Volume
      - DeviceName: "/dev/sdk"
        NoDevice: {}