Script to update Route53 with the current public IP of an instance

dnsupdate.sh

#!/bin/bash

hosted_zone_id="<your Route53 hosted zone id>"
domain_name="<your domain name>"

# Abort script on any errors
set -e

# Get new IP address
ip_address=`curl http://169.254.169.254/latest/meta-data/public-ipv4`

# Build temporary file
cat > ./dnsupdate.json <<EOF
{
  "Changes": [
    {
      "Action": "UPSERT",
      "ResourceRecordSet": {
        "Name": "$domain_name",
        "Type": "A",
        "TTL": 300,
        "ResourceRecords": [
          {
            "Value": "$ip_address"
          }
        ]
      }
    }
  ]
}
EOF

# Call Route53 to update DNS
aws route53 change-resource-record-sets --hosted-zone-id $hosted_zone_id --change-batch file://./dnsupdate.json