Friday, October 21, 2016

Deploying Elasticsearch test node on Oracle Linux

In some cases you want to have a certain type of service running on your Oracle Linux instance just for testing and playing purposes. In my case am experimenting with Elasticsearch from Elastic and I need to install single node Elasticsearch instances every now and than on a new and fresh Oracle Linux instance. Even though it is not that much work it makes more sense to build a script for this.

The below script will install Elasticsearch on Oracle Linux 6 3.8.13-68.2.2.3.el6uek.x86_64 by simply running the script. Elasticsearch is a search engine based on Lucene. It provides a distributed, multitenant-capable full-text search engine with an HTTP web interface and schema-free JSON documents. Elasticsearch is developed in Java and is released as open source under the terms of the Apache License. Elasticsearch is the most popular enterprise search engine followed by Apache Solr, also based on Lucene.

#!/bin/bash


function runMain {
  installJava
  installElasticsearch
  startElasticsearch
}



function packageInstalled () {
  numberOfPackages=`yum list installed | grep $1 | wc -l`
  if [ "$numberOfPackages" -gt "0" ];
   then
       echo "true"
   else
       echo "false"
  fi
}



function installJava {
  javaInstalled=`packageInstalled java-1.8.0-openjdk`
  if [ "$javaInstalled" = "true" ];
   then
       echo "java is already installed"
   else
      echo "installing java"
      yum -y install java-1.8.0-openjdk
  fi
}



function installElasticsearch {
  elasticsearcInstalled=`packageInstalled elasticsearch`
    if [ "$elasticsearcInstalled" = "true" ];
   then
       echo "elasticsearch is already installed"
   else
       echo "importing elastic GPG key"
       rpm --import http://packages.elastic.co/GPG-KEY-elasticsearch

       echo "adding elastic repository to yum"
       echo "" >> /etc/yum.repos.d/public-yum-ol6.repo
       echo "[elastic]" >> /etc/yum.repos.d/public-yum-ol6.repo
       echo "name=Elasticsearch repository for 2.x packages" >> /etc/yum.repos.d/public-yum-ol6.repo
       echo "baseurl=http://packages.elastic.co/elasticsearch/2.x/centos" >> /etc/yum.repos.d/public-yum-ol6.repo
       echo "gpgcheck=1" >> /etc/yum.repos.d/public-yum-ol6.repo
       echo "gpgkey=http://packages.elastic.co/GPG-KEY-elasticsearch" >> /etc/yum.repos.d/public-yum-ol6.repo
       echo "enabled=1" >> /etc/yum.repos.d/public-yum-ol6.repo

       echo "installing elasticsearch"
       yum -y install elasticsearch
   fi
}


function startElasticsearch {
  echo "starting elasticsearch"
  service elasticsearch start
}

runMain

The script has been tested on Oracle Linux 6 running on the Oracle Public Cloud. After completing the script you can see that Elasticsearch is running and listening on port 9200 on both IPv4 and IPv6 by executing the below command:

[root@testbox08 init.d]#
[root@testbox08 init.d]# netstat -ln | grep 9200
tcp        0      0 ::ffff:127.0.0.1:9200       :::*                        LISTEN
tcp        0      0 ::1:9200                    :::*                        LISTEN
[root@testbox08 init.d]#
[root@testbox08 init.d]#

To test if Elasticsearch indeed is working and responding you can do a curl against port 9200 to see the default result from Elasticsearch after a vanilla installation.

[root@testbox08 init.d]#
[root@testbox08 init.d]# curl http://localhost:9200/
{
  "name" : "King Bedlam",
  "cluster_name" : "elasticsearch",
  "cluster_uuid" : "5fd7bOG-RP6MrTbI3denuA",
  "version" : {
    "number" : "2.4.1",
    "build_hash" : "c67dc32e24162035d18d6fe1e952c4cbcbe79d16",
    "build_timestamp" : "2016-09-27T18:57:55Z",
    "build_snapshot" : false,
    "lucene_version" : "5.5.2"
  },
  "tagline" : "You Know, for Search"
}
[root@testbox08 init.d]#
[root@testbox08 init.d]#
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