Amazon Route 53 でDDNSするやつ

route53-ddns.sh

#!/bin/sh
export LANG=C

# 環境変数に AWS_ACCESS_KEY_ID と AWS_SECRET_ACCESS_KEY をセットしておく

DIG="dig +noedns"
CURL="curl -s"
TTL=10

IP4ADDR_CUR=$(${CURL} http://checkip.amazonaws.com)
RC=$?

if [ $RC -ne 0 ]; then
        echo "failed to obtain current ip address" 1>&2
        exit $RC
fi


IP4ADDR_DNS=$(${DIG} +short $(hostname) A)
RC=$?

if [ $RC -ne 0 ]; then
        echo "failed to resolve $(hostname)" 1>&2
        exit $RC
fi

if [ "$IP4ADDR_CUR" != "$IP4ADDR_DNS" ]; then
        cli53 rc --wait --replace $(hostname -d) "$(hostname -s) ${TTL} A ${IP4ADDR_CUR}"
        RC=$?
        ${DIG} $(hostname)
        exit $RC
else
        echo "there's no need to update dns:"
        printf %20s=%s\\n $(hostname) ${IP4ADDR_DNS}
        printf %20s=%s\\n checkip ${IP4ADDR_CUR} 1>&2
        exit 0
fi