EC2 Keypairs.md

  This gist contains code for blog post [EC2 Keypairs](https://jarjuk.wordpress.com/2015/09/23/ec2-keypairs)
  - example-stack.json : CloudFormration JSON template to create stack using example EC2 key-pair
  - verify-keys.sh: a script to verify Amazon fingerprint with OpenSSH private key fingerprint

example-stack.json

   
{
  "AWSTemplateFormatVersion": "2010-09-09",
  "Description": "demo/6 - A simple Amazon EC2 instance created using aws-must tool",
  "Parameters": {
    "InstanceType": {
      "Description": "EC2 reousrce instance type",
      "Type": "String",
      "Default": "t2.micro"
    },

    "KeyName": {
      "Description": "Name of an existing EC2 KeyPair to enable SSH access to the instance",
      "Type": "AWS::EC2::KeyPair::KeyName",
      "Default": "example-key"
    },

    "SSHLocation": {
      "Description": "The IP address range that can be used to SSH to the EC2 instances",
      "Type": "String",
      "Default": "0.0.0.0/0"
    }
  },

  "Mappings": {
    "AWSInstanceType2Arch": {
      "t2.micro": {
        "Arch": "64"
      }
    },
    "AWSRegionArch2AMI": {
      "ap-northeast-1": {
        "64": "ami-90815290"
      },
      "ap-southeast-1": {
        "64": "ami-0accf458"
      },
      "ap-southeast-2": {
        "64": "ami-1dc8b127"
      },
      "cn-north-1": {
        "64": "ami-eae27fd3"
      },
      "eu-central-1": {
        "64": "ami-3248712f"
      },
      "eu-west-1": {
        "64": "ami-d74437a0"
      },
      "sa-east-1": {
        "64": "ami-0f6ced12"
      },
      "us-east-1": {
        "64": "ami-83c525e8"
      },
      "us-west-1": {
        "64": "ami-61b25925"
      },
      "us-gov-west-1": {
        "64": "ami-51513172"
      },
      "us-west-2": {
        "64": "ami-57e8d767"
      }
    }
  },

  "Resources": {
    "MyDefaultSecurityGroup": {
      "Type": "AWS::EC2::SecurityGroup",
      "Properties": {
        "GroupDescription": "Enable SSH access via port 22",
        "SecurityGroupIngress": [
          {
            "IpProtocol": "tcp",
            "FromPort": "22",
            "ToPort": "22",
            "CidrIp": {
              "Ref": "SSHLocation"
            }
          }
        ]
      }
    },

    "MyEC2Instance": {
      "Type": "AWS::EC2::Instance",
      "Properties": {
        "KeyName": {  "Ref": "KeyName" },

        "ImageId": {  "Fn::FindInMap": [  "AWSRegionArch2AMI",   {  "Ref": "AWS::Region"    },
                   {  "Fn::FindInMap": [   "AWSInstanceType2Arch", "t2.micro", "Arch"  ]   }  ]
         },
        "InstanceType": "t2.micro",
        "SecurityGroups": [ { "Ref": "MyDefaultSecurityGroup"    } ]
      }
    }
  },

  "Outputs": {  
    "Exampleinstance": { 
     "Description": "Public IP address of the newly created EC2 instance",
      "Value": {  "Fn::GetAtt": [ "MyEC2Instance",  "PublicIp" ]  }
      
     }
   }
}

verify-keys.sh

#!/bin/bash
   FINGER_PRINT_PUB=$(    aws ec2 describe-key-pairs --query 'KeyPairs[?KeyName==`example-key`].KeyFingerprint' --output text)
   #echo ${FINGER_PRINT_PUB}

   FINGER_PRINT_PRIV=$(   openssl pkey -in example-key  -pubout -outform DER | openssl md5 -c | cut -d' ' -f2)
   #echo ${FINGER_PRINT_PRIV}

   if [  "$FINGER_PRINT_PRIV" == "$FINGER_PRINT_PUB" ]; then
      echo match
   else
      echo WARNING no match
   fi