How to Install Elasticsearch on Debian 10

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 explains how to install Elasticsearch on Debian 10.

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 apt install default-jdk

Verify the Java installation by printing the Java version:

java -version

The output should look something like this:

openjdk version "11.0.6" 2020-01-14
OpenJDK Runtime Environment (build 11.0.6 10-post-Debian-1deb10u1)
OpenJDK 64-Bit Server VM (build 11.0.6 10-post-Debian-1deb10u1, mixed mode, sharing)

Installing Elasticsearch #

Elasticsearch is not available in the standard Debian 10 repositories. We’ll install it from the Elasticsearch APT repository.

Import the repository’s public key using the following wget command:

wget -qO - https://artifacts.elastic.co/GPG-KEY-elasticsearch | sudo apt-key add -

The command above should output OK, which means that the key has been successfully imported, and packages from this repository will be considered trusted.

Add the Elasticsearch repository to the system by running:

sudo sh -c 'echo "deb https://artifacts.elastic.co/packages/7.x/apt stable main" > /etc/apt/sources.list.d/elastic-7.x.list'

Update the packages index and install the Elasticsearch engine:

sudo apt updatesudo apt 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" : "debian10.localdomain",
  "cluster_name" : "elasticsearch",
  "cluster_uuid" : "yCOOHdvYR8mHRs5mNXQdDQ",
  "version" : {
    "number" : "7.6.1",
    "build_flavor" : "default",
    "build_type" : "deb",
    "build_hash" : "aa751e09be0a5072e8570670309b1f12348f023b",
    "build_date" : "2020-02-29T00:15:25.529771Z",
    "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

That’s it. Elasticsearch has been installed on your Debian server.

Configuring Elasticsearch #

Elasticsearch data is stored in the /var/lib/elasticsearch directory. Configuration files are located in /etc/elasticsearch and Java start-up options can be configured in the /etc/default/elasticsearch file.

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, if you are using UFW and you want to allow connections only from 192.168.121.80, enter the following command:

sudo ufw allow from 192.168.100.20 to any port 9200

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 Debian 10.

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

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