ec2 userdata cloudformation

cfn.yml

---
AWSTemplateFormatVersion: '2010-09-09'
Description: Persistantly sets the hostname of a RHEL7 EC2 instance on start
Mappings:
  RegionMap:
    us-east-1:
      '32': ami-6411e20d
      '64': ami-7a11e213
    us-west-1:
      '32': ami-c9c7978c
      '64': ami-cfc7978a
    eu-west-1:
      '32': ami-37c2f643
      '64': ami-31c2f645
    ap-southeast-1:
      '32': ami-66f28c34
      '64': ami-60f28c32
    ap-northeast-1:
      '32': ami-9c03a89d
      '64': ami-a003a8a1
Parameters:
  SSHKey:
    Description: Select your SSH Key
    Type: AWS::EC2::KeyPair::KeyName
  InstanceTypeParameter:
    Type: String
    Default: m4.xlarge
    AllowedValues:
    - t2.micro
    - m4.xlarge
    - m1.large
    Description: Select Instancetype. Default is m4.xlarge.
  InstanceHostname:
    Description: Select your you instance Hostname
    Type: String
    Default: RedHatDevInstance
  InstanceDomainName:
    Description: Select your instance DomainName
    Type: String
    Default: redhat1.org
Resources:
  MyInstance:
    Type: AWS::EC2::Instance
    Properties:
      ImageId:
        Fn::FindInMap:
        - RegionMap
        - Ref: AWS::Region
        - '64'
      InstanceType:
        Ref: InstanceTypeParameter
      KeyName:
        Ref: SSHKey
      UserData:
        Fn::Base64:
          Fn::Join:
          - ''
          - - "#!/bin/bash\n"
            - "# Replace this with your domain\n"
            - DOMAIN=
            - Ref: InstanceDomainName
            - "\n"
            - HOSTNAME=
            - Ref: InstanceHostname
            - "\n"
            - IPV4=/usr/bin/curl -s http://169.254.169.254/latest/meta-data/public-ipv4
            - "\n"
            - "# Set the host name\n"
            - hostname
            - " "
            - Ref: InstanceHostname
            - "\n"
            - echo
            - " "
            - Ref: InstanceHostname
            - "> /etc/hostname\n"
            - "# Add fqdn to hosts file\n"
            - echo 'HOSTNAME=
            - Ref: InstanceHostname
            - "'"
            - ">> /etc/sysconfig/network\n"
            - 'echo ''preserve_hostname: true'' >> /etc/cloud/cloud.cfg

              '
            - 'cat<<EOF > /etc/hosts

              '
            - '127.0.0.1 localhost

              '
            - "$IPV4 $HOSTNAME.$DOMAIN $HOSTNAME\n"
            - EOF