Elasticsearch - Installation and general settings

Sep, 2014

Installation of Elasticsearch is a breeze by which I mean it's as simple as downloading the zip/tar file and unzipping it.


    $ wget https://download.elasticsearch.org/elasticsearch/elasticsearch/elasticsearch-1.3.2.zip
$ unzip elasticsearch-1.3.2.zip -d /usr/share/elasticsearch
$ /usr/share/elasticsearch/bin/plugin -install mobz/elasticsearch-head
$ /usr/share/elasticsearch/bin/plugin -install elasticsearch/elasticsearch-cloud-aws/2.3.0

In the above bash script, we are essentially downloading the file, unzipping and installing couple of plugins for administration and cloud discovery. Now that we have Elasticsearch unzipped, we can optionally provide location to it's data, log and configuration folder. There are two ways to provide Elastisearch this configuration. First way is to provide the paths in the yml configuration file elasticsearch.yml. For example


    #elasticsearch.yml
path.data: /var/elasticsearch/data
path.logs: /var/elasticsearch/logs
path.work: /tmp/elasticsearch

Second way is running Elasticsearch in daemon mode, you can setup the paths in the sysconfig file generally located at /etc/sysconfig/elasticsearch. The configuration in this file is passed onto ES as command line settings when elasticsearch is started.


    #vi /etc/sysconfig/elasticsearch
LOG_DIR=/var/log/elasticsearch
DATA_DIR=/var/lib/elasticsearch
WORK_DIR=/tmp/elasticsearch
CONF_DIR=/etc/elasticsearch
CONF_FILE=/etc/elasticsearch/elasticsearch.yml

Note that the configuration in the elasticsearch.yml file overrides the sysconfig file
But lets say that we using a package manager or puppet scripts to install elasticsearch and now we have no idea where the config files and data directories located. One easy way to get these information is to curl the elasticsearch node endpoint which returns back all the information regarding each node with all path and configuration information


    $ curl http://localhost:9200/_nodes?pretty

"path" : {
    "conf" : "/etc/elasticsearch",
    "data" : "/var/elasticsearch/data",
    "logs" : "/var/elasticsearch/logs",
    "work" : "/tmp/elasticsearch",
    "home" : "/usr/share/elasticsearch"
},
"node" : {
    "data" : "true",
    "master" : "true"
}

More information on the directory structure can be found at Elasticsearch Directory layout
OK, now that we have elasticsearch unzipped and the data directory setup, lets update some minimal but essential Elasticsearch configuration:


    #elasticsearch.yml
cluster.name: es-test-cluster
node.name: es-node-1
node.master: true
node.data: true

List of all configuration can be found at: Elasticsearch configuration file
Note that if the node.name is not provided, Elasticsearch automatically assigns a node name based on Marvel comic characters. This is fine as long as Elasticsearch process does not restart as it will assign a new name again which could be trouble if you are monitoring the ES process by node names.
Now that we have the basic elasticsearch settings updated/added, we can start elasticsearch by running:


    $ /usr/share/elasticsearch/bin/elasticsearch
#(or) in daemon mode
$ /usr/share/elasticsearch/bin/elasticsearch -d
#(or) using init.d script if one installed by the package manager
$ /etc/init.d/elasticsearch start