Map internal to external hostnames on ec2 while using Mesos + Spark

map-ec2-hosts.sh

#!/bin/bash

for i in `cat /root/mesos-ec2/slaves`; 
do 
  ssh $i 'echo -n `hostname`" "; nslookup `hostname` | grep Address | grep 10'; 
done | awk '{print $1" "$3}' > /tmp/internal

for i in `cat /root/mesos-ec2/slaves`; 
do 
  ssh $i "echo -n $i' '; nslookup $i | grep Address | grep 10"; 
done | awk '{print $1" "$3}' > /tmp/external

join /tmp/internal /tmp/external -1 2 -2 2 | awk '{print $2" "$3}'