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

dnsupdate.sh

#!/bin/bash

hosted_zone_id='Z57Q212345678'
domain_name='server.example.com'

# Abort script on any errors
set -e

# Get new IP address
ip_address=$(curl -s 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