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BASH Script to keep Route53 updated with your current external IP address
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#!/bin/bash | |
# place this script in /root | |
# add the following line to end of crontab | |
# @reboot /root/update-route53.sh | |
#update ZONEID and RECORDSET with values for this instance | |
# | |
# Hosted Zone ID e.g. BJBK35SKMM9OE | |
ZONEID="zzzzz" | |
# The CNAME you want to update e.g. hello.example.com | |
RECORDSET="your.domain.com" | |
# More advanced options below | |
# The Time-To-Live of this recordset | |
TTL=300 | |
# Change this if you want | |
COMMENT="Auto updating @ `date`" | |
# Change to AAAA if using an IPv6 address | |
TYPE="A" | |
# Get the external IP address from AWS | |
IP=$(curl http://checkip.amazonaws.com) | |
# not that important, mostly for graceful failure | |
function valid_ip() | |
{ | |
local ip=$1 | |
local stat=1 | |
if [[ $ip =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$ ]]; then | |
OIFS=$IFS | |
IFS='.' | |
ip=($ip) | |
IFS=$OIFS | |
[[ ${ip[0]} -le 255 && ${ip[1]} -le 255 \ | |
&& ${ip[2]} -le 255 && ${ip[3]} -le 255 ]] | |
stat=$? | |
fi | |
return $stat | |
} | |
# Get current dir | |
# (from http://stackoverflow.com/a/246128/920350) | |
DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )" | |
LOGFILE="$DIR/update-route53.log" | |
IPFILE="$DIR/update-route53.ip" | |
if ! valid_ip $IP; then | |
echo "Invalid IP address: $IP" >> "$LOGFILE" | |
exit 1 | |
fi | |
# Check if the IP has changed | |
if [ ! -f "$IPFILE" ] | |
then | |
touch "$IPFILE" | |
fi | |
if grep -Fxq "$IP" "$IPFILE"; then | |
# code if found | |
echo "IP is still $IP. Exiting" >> "$LOGFILE" | |
exit 0 | |
else | |
echo "IP has changed to $IP" >> "$LOGFILE" | |
# Fill a temp file with valid JSON | |
TMPFILE=$(mktemp /tmp/temporary-file.XXXXXXXX) | |
cat > ${TMPFILE} << EOF | |
{ | |
"Comment":"$COMMENT", | |
"Changes":[ | |
{ | |
"Action":"UPSERT", | |
"ResourceRecordSet":{ | |
"ResourceRecords":[ | |
{ | |
"Value":"$IP" | |
} | |
], | |
"Name":"$RECORDSET", | |
"Type":"$TYPE", | |
"TTL":$TTL | |
} | |
} | |
] | |
} | |
EOF | |
# Update the Hosted Zone record | |
aws route53 change-resource-record-sets \ | |
--hosted-zone-id $ZONEID \ | |
--change-batch file://"$TMPFILE" >> "$LOGFILE" | |
echo "" >> "$LOGFILE" | |
# Clean up | |
rm $TMPFILE | |
fi | |
# All Done - cache the IP address for next time | |
echo "$IP" > "$IPFILE" |
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