Script to install a rolling upgrade of ElasticSearch, for a single node setup. Checked in ubuntu

es_rolling_upgrade.sh

#!/bin/bash

display_usage() {
	echo "This script must be run with super-user privileges."
	echo -e "\nUsage:\n$0 [es-version e.g.: "2.3.3"] \n"
}

# check whether user had supplied -h or --help . If yes display usage
if [[ ( $# == "--help") ||  $# == "-h" ]]
then
  display_usage
  exit 0
fi

if [ ! $# -eq 1 ]; then
    echo "Error: wrong parameters. Please supply the ES version number to install. E.g. '2.3.3'"
    exit 1
else
  if [[ $1 =~ ^[0-9](\.[0-9])+$ ]]; then
    echo "Will upgrade to ES version $1"
  else
    echo "$1: invalid version number"
    exit 1
  fi
fi

# display usage if the script is not run as root user
if [[ $USER != "root" ]]; then
  echo "This script must be run as root!"
  exit 1
fi

if [ -f elasticsearch-$1.deb ];
then
   echo "elasticsearch-$1.deb found"
else
   echo "Downloading elasticsearch-$1.deb"
  wget https://download.elasticsearch.org/elasticsearch/release/org/elasticsearch/distribution/deb/elasticsearch/$1/elasticsearch-$1.deb

  if [ $? -eq 0 ]
  then
    echo "Downloaded elasticsearch-$1.deb"
  else
    echo "Could not download elasticsearch-$1.deb" >&2
    exit 2
  fi
fi

#Stop if anything fails
set -e

cp /etc/elasticsearch/elasticsearch.yml elasticsearch.yml.prev

curl -XPUT 'http://localhost:9200/_cluster/settings' -d'
{
  "transient": {
    "cluster.routing.allocation.enable": "none"
  }
}'

curl -XPOST 'http://localhost:9200/_flush/synced'
service elasticsearch stop

dpkg -i elasticsearch-$1.deb

cd /usr/share/elasticsearch && bin/plugin remove cloud-aws
cd /usr/share/elasticsearch && bin/plugin install cloud-aws

service elasticsearch start

set +e

es_running="0"
for i in $(seq 1 5);
   do
     sleep 5
     curl http://localhost:9200
     if [ $? -eq 0 ]; then
        es_running="1"
        break
     fi
   done

if [ $es_running -eq "1" ]; then
  curl -XPUT 'http://localhost:9200/_cluster/settings?pretty' -d'
  {
    "transient": {
      "cluster.routing.allocation.enable": "all"
    }
  }'
  if [ $? -eq 0 ]; then
     echo "cluster.routing.allocation.enable set to all OK"
  else
     echo "Could not set cluster.routing.allocation.enable. Check logs"
  fi
else
  echo "Error: could not start elasticsearch service. Check logs"
fi