create a digitalocean droplet with elasticsearch enabled to listen private network

userdata-elasticsearch.sh

#!/bin/sh

export PRIVATEADDRS=$(curl -s http://169.254.169.254/metadata/v1/interfaces/private/0/ipv4/address)


apt-get update

sudo apt-get install default-jre -y

wget -O /tmp/es https://download.elastic.co/elasticsearch/release/org/elasticsearch/distribution/deb/elasticsearch/2.4.1/elasticsearch-2.4.1.deb

sudo dpkg -i /tmp/es

sudo echo "network.host: $PRIVATEADDRS" >> /etc/elasticsearch/elasticsearch.yml 

sudo systemctl enable elasticsearch.service

sudo service elasticsearch restart

dd if=/dev/zero of=/var/swap bs=512 count=2097152
mkswap /var/swap 
chmod 0600 /var/swap 
swapon /var/swap