Elasticsearch

External

• https://www.elastic.co/products/elasticsearch

Internal

• System Design
• MediaWiki CirrusSearch
• Elastic Stack
• Logstash
• Kibana
• Beats

Overview

ElasticSearch is an open source, object store and a distributed search and analytics engine. It comes with a developer-friendly query language covering structured, unstructured and time-series data. By default, ElasticSearch uses TCP port 9300.

Installation

For pre-7 versions, Java must be installed as a prerequisite and JAVA_HOME set in the root's environment in /etc/profile.d/java.sh. See:

Setting Configuration for all Users, Including root

For 7 and newer, Java is embedded.

Download the latest RPM from https://www.elastic.co/guide/en/elasticsearch/reference/current/install-elasticsearch.html → Install Electric Search with RPM → https://www.elastic.co/guide/en/elasticsearch/reference/current/rpm.html

#wget https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-7.15.2-x86_64.rpm
wget https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-6.8.20.rpm
#sudo rpm --install elasticsearch-7.15.2-x86_64.rpm
sudo rpm --install elasticsearch-6.8.20.rpm

Enable start at boot. As root:

systemctl daemon-reload
systemctl enable elasticsearch.service

Smoke test:

curl http://localhost:9200/
{
  "name" : "pkb.local",
  "cluster_name" : "elasticsearch",
  "cluster_uuid" : "37KaoJd3Q6qyBJSU0-7eQw",
  "version" : {
    "number" : "7.15.2",
    "build_flavor" : "default",
    "build_type" : "rpm",
    "build_hash" : "93d5a7f6192e8a1a12e154a2b81bf6fa7309da0c",
    "build_date" : "2021-11-04T14:04:42.515624022Z",
    "build_snapshot" : false,
    "lucene_version" : "8.9.0",
    "minimum_wire_compatibility_version" : "6.8.0",
    "minimum_index_compatibility_version" : "6.0.0-beta1"
  },
  "tagline" : "You Know, for Search"
}

Configuration

https://www.elastic.co/guide/en/elasticsearch/reference/current/rpm.html#rpm-configuring

/etc/elasticsearch/elasticsearch.yml

Operations

Layout

https://www.elastic.co/guide/en/elasticsearch/reference/current/rpm.html#rpm-layout

$ES_HOME: /usr/share/elasticsearch

State: /var/lib/elasticsearch

Start/Stop

systemctl stop elasticsearch.service
systemctl start elasticsearch.service

Logs

/var/log/elasticsearch/

Queries

Indices

curl http://localhost:9200/_cat/indices?v

curl http://localhost:9200/_cat/aliases?h=a

Interact with an Index

curl http://localhost:9200/<index-name>/
curl http://localhost:9200/<index-name>/_count

ElasticSearch and OpenShift

ElasticSearch and OpenShift