DevOps Classroom Series – 17/Jul/2020

Installing Elastic Search

  • Used instructions from here to install elastic search Preview
  • Elastic search by default is configured to run on 9200. Try accessing http://<public ip>:9200 Preview
  • To fix this lets change configuration in /etc/elasticsearch/elasticsearch.yml Preview
  • To know complete information about configuration files Refer Here
  • For network.host setting Refer Here
  • Basic Elastic search settings are configured to work with localhost, if you need make them work on production, focus on network configurations first. Preview

Lets install Kibana on the same server

  • Used Instructions From here to install kibana
  • Since we configured repository on this machine already, directly execute command
sudo apt-get update && sudo apt-get install kibana

Preview

  • Lets change the configuration of kibana (/etc/kibana/kibana.yml) Preview Preview
  • Restart kibana after changing configurations and navigate to http://<publicip&gt;:5601 Preview Preview
  • Naviagate to DevTools Preview Preview
  • Console in the DevTools will be our playground to understand elastic search concepts Preview Preview
  • Here we have simply sent the GET / query. This is equivalent to curl command that we send to Elastic search for testing the setup curl http://<elasticsearchipaddress&gt;:9200

Core Concepts of Elastic Search

  • We need the understand the following core abstractions

    • Indexes
    • Types
    • Documents
    • Clusters
    • Nodes
    • Shards and replicas
    • Mappings and types
    • Inverted Indexes
  • Lets Execute the following in the Kibana Dev Console

PUT /catalog/_doc/1
{
    "title": "Linux Bible, 9th Edition",
    "author": "Christopher Negus",
    "ISBN": "978-1-118-99987-5",
    "price": 50,
    "pages": 912,
    "pubished_date": "april 2015"

}

Preview

  • To understand what has happened in the above image, lets try to understand core abstractions

Index

  • An index is a container that stores and manages document of single type in Elastic.
  • Concept of index in Elastic Search is almost equivalent to the database in relational database. However consider index as one database with only one table with multiple records. Preview
  • Index is logical container of Type. and Type will be logical collections records of the type defined
  • Database = Index Table = Type Records = Documents (Json)
  • From Elastic Search 7.0 one index can contain only one type, attempting add one more type in into index will create error.

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