How to Install Elasticsearch on CentOS 8

Elasticsearch is an open-source distributed full-text search and analytics engine. It supports RESTful operations and allows you to store, search, and analyze big volumes of data in real-time. Elasticsearch is one of the most popular search engines powering applications that have complex search requirements such as big e-commerce stores and analytic applications.

This tutorial covers the installation of Elasticsearch on CentOS 8.

Installing Java #

Elasticsearch is a Java application, so the first step is to install Java.

Run the following as root or user with sudo privileges
command to install the OpenJDK package:

sudo dnf install java-11-openjdk-devel

Verify the Java installation by printing the Java version
:

java -version

The output should look something like this:

openjdk version "11.0.5" 2019-10-15 LTS
OpenJDK Runtime Environment 18.9 (build 11.0.5+10-LTS)
OpenJDK 64-Bit Server VM 18.9 (build 11.0.5+10-LTS, mixed mode, sharing)

Installing Elasticsearch #

Elasticsearch is not available in the standard CentOS 8 repositories. We’ll install it from the Elasticsearch RPM repository.

Import the repository’s GPG using the rpm
command:

sudo rpm --import https://artifacts.elastic.co/GPG-KEY-elasticsearch

Open your text editor and create the repository file the /etc/yum.repos.d directory:

sudo nano /etc/yum.repos.d/elasticsearch.repo

Paste the following content into the file:

/etc/yum.repos.d/elasticsearch.repo

[elasticsearch-7.x]
name=Elasticsearch repository for 7.x packages
baseurl=https://artifacts.elastic.co/packages/7.x/yum
gpgcheck=1
gpgkey=https://artifacts.elastic.co/GPG-KEY-elasticsearch
enabled=1
autorefresh=1
type=rpm-md

Save the file and close your text editor.

Now that the repository is enabled, install the Elasticsearch package by typing:

sudo dnf install elasticsearch

Once the installation process is complete, start, and enable the service:

sudo systemctl enable elasticsearch.service --now

To verify that Elasticsearch is running, use curl
to send an HTTP request to port 9200 on localhost:

curl -X GET "localhost:9200/"

The output will look something like this:

{
  "name" : "centos8.localdomain",
  "cluster_name" : "elasticsearch",
  "cluster_uuid" : "V_mfjn2PRJqX3PlZb_VD7w",
  "version" : {
    "number" : "7.6.0",
    "build_flavor" : "default",
    "build_type" : "rpm",
    "build_hash" : "7f634e9f44834fbc12724506cc1da681b0c3b1e3",
    "build_date" : "2020-02-06T00:09:00.449973Z",
    "build_snapshot" : false,
    "lucene_version" : "8.4.0",
    "minimum_wire_compatibility_version" : "6.8.0",
    "minimum_index_compatibility_version" : "6.0.0-beta1"
  },
  "tagline" : "You Know, for Search"
}

It may take 5-10 seconds for the service to start. If you see curl: (7) Failed to connect to localhost port 9200: Connection refused, wait for a few seconds and try again.

To view the messages logged by the Elasticsearch service, use the following command:

sudo journalctl -u elasticsearch

At this point, you have Elasticsearch installed on your CentOS server.

Configuring Elasticsearch #

Elasticsearch data is stored in the /var/lib/elasticsearch directory, configuration files are located in /etc/elasticsearch.

By default, Elasticsearch is configured to listen on localhost only. If the client connecting to the database is also running on the same host and you are setting up a single node cluster, you don’t need to change the default configuration file.

Remote Access #

Out of box Elasticsearch, does not implement authentication, so it can be accessed by anyone who can access the HTTP API. If you want to allow remote access to your Elasticsearch server, you will need to configure your firewall
and allow access to the Elasticsearch port 9200 only from trusted clients.

For example, to allow connections only from 192.168.121.80, enter the following command:

Run the following command to allow assess from the remote trusted IP address on port 9200 :

sudo firewall-cmd --new-zone=elasticsearch --permanentsudo firewall-cmd --reloadsudo firewall-cmd --zone=elasticsearch --add-source=192.168.121.80/32 --permanentsudo firewall-cmd --zone=elasticsearch --add-port=9200/tcp --permanentsudo firewall-cmd --reload

Later, if you want to allow access from another IP Address use:

sudo firewall-cmd --zone=elasticsearch --add-source=<IP_ADDRESS> --permanentsudo firewall-cmd --reload

Once the firewall is configured, the next step is to edit the Elasticsearch configuration and allow Elasticsearch to listen for external connections.

To do so, open the elasticsearch.yml configuration file:

sudo nano /etc/elasticsearch/elasticsearch.yml

Search for the line that contains network.host, uncomment it, and change the value to 0.0.0.0:

/etc/elasticsearch/elasticsearch.yml

If you have multiple network interfaces on your machine, specify the interface IP address to force Elasticsearch to listen only to the given interface.

Restart the Elasticsearch service for the changes to take effect:

sudo systemctl restart elasticsearch

That’s it. You can now connect to the Elasticsearch server from the remote location.

Conclusion #

We’ve shown you how to install Elasticsearch on CentOS 8.

To learn more about Elasticsearch, visit the official documentation
page.

If you hit a problem or have feedback, leave a comment below.