How to install Elasticsearch on Ubuntu 20.04

In this tutorial, we are going to learn how to install Elasticsearch on Ubuntu 20.04.

Elasticsearch is a distributed, free and open search and analytic engine for data e.g textual, numerical, structured, and unstructured data.

Elasticsearch is known for its simple rest API, distributed in nature, speed, and scalability. These are the features that make Elasticsearch useful.

Elasticsearch is the central component of Elastic Stack often referred to as ELK that is Elasticsearch, Logstash, and Kibana which are free and open tools for data ingestion, enrichment, storage, analysis, and visualization.

Prerequisites

• Have an Ubuntu 20.04 which is upto date
• Know basic terminal commands

Installing Elasticsearch on Ubuntu 20.04

1. Install system update

Before we can begin the installation, we need to update our system repositories to make them up to date.

$ sudo apt update
$ sudo apt upgrade -y 
# restart the system as well for changes to take effect immediately.

2. import Elasticsearch PGP key

PGP key is for signing the Elasticsearch. We need to download it which helps with security concerns.

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

You may need to install apt-transport-https as prerequisites even though Ubuntu 20.04 comes preinstalled but its always necessary as a precaution. To install run the following command

$ sudo apt install apt-transport-https

Then we need to add Elastic to source.list.d with the following command

$ echo "deb https://artifacts.elastic.co/packages/7.x/apt stable main" | sudo tee /etc/apt/sources.list.d/elastic-7.x.list

After, you need to update your system repositories again

$ sudo apt update 
Hit:1 http://security.ubuntu.com/ubuntu focal-security InRelease
Get:2 https://artifacts.elastic.co/packages/7.x/apt stable InRelease [13.7 kB]                                  
Hit:3 http://mirrors.digitalocean.com/ubuntu focal InRelease                                                    
Hit:4 https://repos-droplet.digitalocean.com/apt/droplet-agent main InRelease
Hit:5 http://mirrors.digitalocean.com/ubuntu focal-updates InRelease
Hit:6 http://mirrors.digitalocean.com/ubuntu focal-backports InRelease
Get:7 https://artifacts.elastic.co/packages/7.x/apt stable/main amd64 Packages [89.7 kB]
Fetched 103 kB in 1s (129 kB/s)    
Reading package lists... Done
Building dependency tree       
Reading state information... Done
All packages are up to date.

3. Install Elasticsearch on Ubuntu 20.04

We are now ready to install Elasticsearch. Use the following command to install

$ sudo apt install elasticsearch

You will get the following output

Output
The following NEW packages will be installed:
  elasticsearch
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 344 MB of archives.
After this operation, 552 MB of additional disk space will be used.
Get:1 https://artifacts.elastic.co/packages/7.x/apt stable/main amd64 elasticsearch amd64 7.16.2 [344 MB]
Fetched 344 MB in 6s (58.7 MB/s)        
Selecting previously unselected package elasticsearch.
(Reading database ... 94648 files and directories currently installed.)
Preparing to unpack .../elasticsearch_7.16.2_amd64.deb ...
Creating elasticsearch group... OK
Creating elasticsearch user... OK
Unpacking elasticsearch (7.16.2) ...
Setting up elasticsearch (7.16.2) ...
### NOT starting on installation, please execute the following statements to configure elasticsearch service to start automatically using systemd
 sudo systemctl daemon-reload
 sudo systemctl enable elasticsearch.service
### You can start elasticsearch service by executing
 sudo systemctl start elasticsearch.service
Created elasticsearch keystore in /etc/elasticsearch/elasticsearch.keystore
Processing triggers for systemd (245.4-4ubuntu3.15) ...

4. Configuring Elasticsearch

After installation we will need to edit the main configuration file, that is elasticsearch.yaml file. It is located at the /etc/elasticsearch.

We need to adjust the network hosts’ config. Elasticsearch listens on port 9200 and therefore to restrict outside access of your Elasticsearch, we need to only allow localhost access. Uncomment the line network.host

Open your preferred editor

$ sudo nano /etc/elasticsearch/elasticsearch.yml

Now we need to reload and start Elasticsearch service with systemctl command as specified at the output above

$ sudo systemctl daemon-reload
$ sudo systemctl enable elasticsearch.service
$ sudo systemctl start elasticsearch.service

You can check the status of Elasticsearch with the following command

$ sudo systemctl status elasticsearch

The following will be the output

output
● elasticsearch.service - Elasticsearch
     Loaded: loaded (/lib/systemd/system/elasticsearch.service; enabled; vendor preset: enabled)
     Active: active (running) since Thu 2022-01-13 12:13:42 UTC; 1min 38s ago
       Docs: https://www.elastic.co
   Main PID: 17888 (java)
      Tasks: 59 (limit: 1136)
     Memory: 703.1M
     CGroup: /system.slice/elasticsearch.service
             ├─17888 /usr/share/elasticsearch/jdk/bin/java -Xshare:auto -Des.networkaddress.cache.ttl=60 -Des.ne>
             └─18057 /usr/share/elasticsearch/modules/x-pack-ml/platform/linux-x86_64/bin/controller

Jan 13 12:12:56 ubuntu systemd[1]: Starting Elasticsearch...
Jan 13 12:13:42 ubuntu systemd[1]: Started Elasticsearch.

If the service is up and running then we are good to continue

5. Testing Elasticsearch

We can test the Elasticsearch if its nodes are running on port 9200 by sending a request

$ curl -X GET 'http://localhost:9200'

You will get the following as output

output
{
  "name" : "ubuntu",
  "cluster_name" : "elasticsearch",
  "cluster_uuid" : "QNag836iRrOdwCC6kYlV9A",
  "version" : {
    "number" : "7.16.2",
    "build_flavor" : "default",
    "build_type" : "deb",
    "build_hash" : "2b937c44140b6559905130a8650c64dbd0879cfb",
    "build_date" : "2021-12-18T19:42:46.604893745Z",
    "build_snapshot" : false,
    "lucene_version" : "8.10.1",
    "minimum_wire_compatibility_version" : "6.8.0",
    "minimum_index_compatibility_version" : "6.0.0-beta1"
  },
  "tagline" : "You Know, for Search"
}

As you can see from the output above its running as required on port 9200

Conclusion

We have successfully installed and configured Elasticsearch on Ubuntu 20.04. You can get detailed views on Elasticsearch documentation.