Updates a AWS Route53 record with the machine's current IP address.

route53-dyndns.sh

#!/bin/bash
set -o nounset # Treat unset variables as an error when performing parameter expansion
set -o errexit # Halt script on error
set -o xtrace # Print a trace of simple commands and their arguments after expansion and before execution

HOSTED_ZONE_ID=YOUR_HOSTED_ZONE_ID
DNS_NAME=WWW.EXAMPLE.COM
IP=$(curl -s https://checkip.amazonaws.com)

CHANGE_ID=$(aws route53 change-resource-record-sets \
  --hosted-zone-id "${HOSTED_ZONE_ID}" \
  --change-batch file://<(echo "{ \"Changes\": [ { 
     \"Action\": \"UPSERT\", 
     \"ResourceRecordSet\": {
       \"Name\": \"${DNS_NAME}\",
       \"Type\": \"A\",
       \"TTL\": 300,
       \"ResourceRecords\": [ {
         \"Value\": \"${IP}\"
       }]}}]}") \
  --output text --query ChangeInfo.Id)

  aws route53 wait resource-record-sets-changed --id "${CHANGE_ID}"

The AWS IAM user running this command requires the following permissions:

• route53:ChangeResourceRecordSets for the resource arn:aws:route53:::hostedzone/HOSTED_ZONE_ID
• route53:GetChange for the resource arn:aws:route53:::change/*

Adapted from this guide:
https://community.ubnt.com/t5/EdgeRouter/HOWTO-update-a-AWS-Route53-record-with-your-router-s-public-IP/td-p/1349799