template.yml

Parameters:
  InstanceImageIdParameter:
    Type: AWS::EC2::Image::Id 
    Default: 'ami-5055cd3f'
  InstanceTypeParameter:
    Type: String
    Default: t2.micro
  InstanceKeyNameParameter:
    Type: String
  InstanceNameParameter:
    Type: String
    Default: 'aws-tags-to-env-instance'

Resources:
  MyInstanceRole:
    Type: AWS::IAM::Role
    Properties:
      RoleName: aws-tags-as-env-default
      AssumeRolePolicyDocument:
        Version: '2012-10-17'
        Statement: 
          - Effect: Allow
            Principal:
              Service: ec2.amazonaws.com
            Action:
              - sts:AssumeRole
  DescribeTagsPolicy:
    Type: AWS::IAM::Policy
    Properties:
      PolicyName: 'Ec2-DescribeTags'
      PolicyDocument:
        Statement:
          - Effect: Allow
            Action: 
              - "ec2:DescribeTags"
            Resource: "*"
      Roles:
        - Ref: MyInstanceRole
  MyInstanceProfile:
    Type: AWS::IAM::InstanceProfile
    DependsOn: MyInstanceRole
    Properties:
      Roles:
        - Ref: MyInstanceRole
      InstanceProfileName: aws-tags-as-env-instanceProfile
  Instance:
    Type: AWS::EC2::Instance
    DependsOn: MyInstanceProfile
    Properties:
      ImageId: 
        Ref: InstanceImageIdParameter
      InstanceType: 
        Ref: InstanceTypeParameter
      KeyName: 
        Ref: InstanceKeyNameParameter
      IamInstanceProfile: 
        Ref: MyInstanceProfile
      UserData:
        Fn::Base64: 
          Fn::Sub: |
            #!/bin/bash

            # install pip
            OS=`cat /etc/os-release | grep '^NAME=' |  tr -d \" | sed 's/\n//g' | sed 's/NAME=//g'`

            if [ "$OS" == "Ubuntu" ]; then
              apt-get -y update
              apt-get -y install python-pip
            elif [ "$OS" == "Amazon Linux AMI" ]; then
              yum update -y 
              yum install -y python-pip
            fi

            # install aws-cli
            pip install --upgrade pip &> /dev/null
            pip install awscli --ignore-installed six &> /dev/null

            # add boot script which loads environment variables
            cat > /etc/profile.d/export_instance_tags.sh << 'EOF'

            # fetch instance info
            INSTANCE_ID=$(curl -s http://169.254.169.254/latest/meta-data/instance-id)
            REGION=${AWS::Region}

            # export instance tags
            export_statement=$(aws ec2 describe-tags --region "$REGION" \
                                    --filters "Name=resource-id,Values=$INSTANCE_ID" \
                                    --query 'Tags[?!contains(Key, `:`)].[Key,Value]' \
                                    --output text | \
                                    sed -E 's/^([^\s\t]+)[\s\t]+([^\n]+)$/export \1="\2"/g')
            eval $export_statement

            # export instance info
            export INSTANCE_ID
            export REGION

            EOF
      Tags:
        - Key: Name
          Value: 'My Awesome Instance'
        - Key: INSTANCE_ROLE_ARN
          Value: 
            Fn::GetAtt:
              - MyInstanceRole
              - Arn
        - Key: GREETING
          Value: "Hello, world!"
        - Key: TAG1
          Value: "My awesome tag #1"