spot

#!/bin/sh
# script that runs on the permanent control host to reclaim IP address when spot instance dies.
# This is really just a backstop in case the spot instance doesn't voluntarily reassign it before dying.

if [ -f /etc/ec2spotter ]
then
	# safety check - I'm not the control, I'm the spot instance!
	exit 0
fi

PATH=/usr/local/bin/:$PATH

cd $(dirname $0)
CONF=$(hostname -s).conf
. ./$CONF || exit 1

#
# First check if the IP address needs to be reclaimed. This could happen if the spot instance had a sudden failure.
#

ipOwner=$(aws ec2 describe-addresses --allocation-ids $ec2spotter_elastic_ip | jq -r '.Addresses[0].InstanceId') &&
self=$(curl -s http://169.254.169.254/latest/meta-data/instance-id) &&

if [ "$ipOwner" = "null" ] || [ "$ipOwner" = "" ]
then
	# reclaim the public IP address
	aws ec2 associate-address --instance-id $self --allocation-id $ec2spotter_elastic_ip --allow-reassociation
	echo "Elastic IP $ec2spotter_elastic_ip reclaimed to instance $self"
fi

#
# Next check if the spot instance needs to be relaunched.
#
if [ -f spot.tmp ]
then
	spotId=$(jq -r '.SpotInstanceRequests[0].SpotInstanceRequestId' < spot.tmp)
	state=$(aws ec2 describe-spot-instance-requests --spot-instance-request-ids $spotId | jq -r '.SpotInstanceRequests[0].State')

	if [ ! "$state" = "active" ] && [ ! "$state" = "open" ]
	then
		echo self=$self oldSpotId=$spotId state=$state $(hostname)
		mv -f spot.tmp spot.tmp-old # remove to avoid weird loops and race conditions
		./relaunch $CONF
	fi
fi