The Dumbest Dynamic DNS [Route53]

README.md

A Dumb Route53 Dynamic DNS Solution

There's really not much to it.

You'll need an AWS Route53 hosted zone and a suitable AWS user. Install and configure AWS CLI. Update ddns-sync.sh variables (DNS_NAME and HOSTED_ZONE_ID) appropriately. Then,

$ cp ddns-sync.sh      ${HOME}
$ cp ddns-sync.service ${HOME}/.config/systemd/user/
$ cp ddns-sync.timer   ${HOME}/.config/systemd/user/
$ systemctl --user enable ddns-sync.service
$ systemctl --user enable ddns-sync.timer
$ systemctl --user start  ddns-sync.timer

If your host's public IP changes, the script will update the DNS route.

Enjoy 😊

aws-route53-change-resource-policy.json

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "route53:ChangeResourceRecordSets"
            ],
            "Resource": [
                "arn:aws:route53:::hostedzone/<YOUR HOSTED ZONE ID>"
            ]
        }
    ]
}

ddns-sync.service

[Unit]
Description=Sync an AWS Route53 DNS Alias Record to Public Address of Current Host

[Service]
Type=oneshot
ExecStart=%h/ddns-sync.sh

[Install]
WantedBy=default.target

ddns-sync.sh

#!/usr/bin/env bash

DNS_NAME=<YOUR DNS NAME>
HOSTED_ZONE_ID=<YOUR HOSTED ZONE ID>

RESOLV_ADDR=($(getent hosts ${DNS_NAME}))
RESOLV_ADDR="${RESOLV_ADDR[0]}"

PUBLIC_IP="$(curl -s https://checkip.amazonaws.com)"

if [[ "${RESOLV_ADDR}" == "${PUBLIC_IP}" ]]; then
	exit 0
fi

echo "Upserting DNS alias record ${DNS_NAME} in hosted zone ${HOSTED_ZONE_ID} from ${RESOLV_ADDR} to ${PUBLIC_IP}"

aws route53 change-resource-record-sets --hosted-zone-id ${HOSTED_ZONE_ID} --change-batch "
{
	\"Changes\": [{
		\"Action\": \"UPSERT\",
		\"ResourceRecordSet\": {
			\"Name\": \"${DNS_NAME}\",
			\"Type\": \"A\",
			\"TTL\": 900,
			\"ResourceRecords\": [{
				\"Value\": \"${PUBLIC_IP}\"
			}]
		}
	}]
}"

ddns-sync.timer

[Unit]
Description=Sync an AWS Route53 DNS Alias Record to Public Address of Current Host

[Timer]
OnBootSec=5min
OnUnitActiveSec=10min

[Install]
WantedBy=timers.target