Top 50 Elasticsearch Multiple Choice Questions and Answers

What is Elasticsearch?

The short version of Elasticsearch is that we help everyone find what they need faster—from employees who need documents from your intranet to customers browsing online for the perfect pair of shoes. But the more technical version goes a little more like this:

Elasticsearch is a distributed, free and open search and analytics engine for all types of data, including textual, numerical, geospatial, structured, and unstructured. Elasticsearch is built on Apache Lucene and was first released in 2010 by Elasticsearch N.V. (now known as Elastic). Known for its simple REST APIs, distributed nature, speed, and scalability.

Elasticsearch is the central component of the Elastic Stack, a set of free and open tools for data ingestion, enrichment, storage, analysis, and visualization.

Commonly referred to as the ELK Stack (after Elasticsearch, Logstash, and Kibana), the Elastic Stack now includes a rich collection of lightweight shipping agents known as Beats for sending data to Elasticsearch.

What is used for?

The speed and scalability of Elasticsearch and its ability to index many types of content mean that it can be used for a number of use cases:

  • Application search
  • Website search
  • Enterprise search
  • Logging and log analytics
  • Infrastructure metrics and container monitoring
  • Application performance monitoring
  • Geospatial data analysis and visualization
  • Security analytics
  • Business analytics

What is an Elasticsearch index?

An Elasticsearch index is a collection of documents that are related to each other. Elasticsearch stores data as JSON documents. Each document correlates a set of keys (names of fields or properties) with their corresponding values (strings, numbers, Booleans, dates, arrays of values, geolocations, or other types of data).

Elasticsearch uses a data structure called an inverted index, which is designed to allow very fast full-text searches. An inverted index lists every unique word that appears in any document and identifies all of the documents each word occurs in.

During the indexing process, Elasticsearch stores documents and builds an inverted index to make the document data searchable in near real-time. Indexing is initiated with the index API, through which you can add or update a JSON document in a specific index.

What is Logstash used for?

Logstash, one of the core products of the Elastic Stack, is used to aggregate and process data and send it to Elasticsearch. Logstash is an open source, server-side data processing pipeline that enables you to ingest data from multiple sources simultaneously and enrich and transform it before it is indexed into Elasticsearch.

What is Kibana used for?

Kibana is a data visualization and management tool for Elasticsearch that provides real-time histograms, line graphs, pie charts, and maps. Kibana also includes advanced applications such as Canvas, which allows users to create custom dynamic infographics based on their data, and Elastic Maps for visualizing geospatial data.

Why use Elasticsearch?

Elasticsearch is fast. Because Elasticsearch is built on top of Lucene, it excels at full-text search. Elasticsearch is also a near real-time search platform, meaning the latency from the time a document is indexed until it becomes searchable is very short — typically one second. As a result, Elasticsearch is well suited for time-sensitive use cases such as security analytics and infrastructure monitoring.

Elasticsearch is distributed by nature. The documents stored in Elasticsearch are distributed across different containers known as shards, which are duplicated to provide redundant copies of the data in case of hardware failure. The distributed nature of Elasticsearch allows it to scale out to hundreds (or even thousands) of servers and handle petabytes of data.

Elasticsearch comes with a wide set of features. In addition to its speed, scalability, and resiliency, Elasticsearch has a number of powerful built-in features that make storing and searching data even more efficient, such as data rollups and index lifecycle management.

The Elastic Stack simplifies data ingest, visualization, and reporting. Integration with Beats and Logstash makes it easy to process data before indexing into Elasticsearch. And Kibana provides real-time visualization of Elasticsearch data as well as UIs for quickly accessing application performance monitoring (APM), logs, and infrastructure metrics data.

ElasticSearch Search Raptors Interview Questions and Answers

Q.1 For identification, a node is assigned with an ________.

       A. MMID

       B. Uniform Resource Locator

       C. Uniform Resource Indicator

       D. Universally Unique Identifier

Ans : MMID


Q.2 Elasticsearch is a/an ________.

       A. Search Engine

       B. Analytics Engine

       C. Both the options

       D. None of the options

Ans : Both the options


Q.3 What is an Index?

       A. Collection of types

       B. Collection of documents having similar characteristics

       C. Collection of documents having non-similar characteristics

       D. Collection of nodes

Ans : Collection of documents having similar characteristics


Q.4 Elasticsearch is based on _______ architecture and provides __________ endpoint.

       A. REST, API

       B. API, REST

       C. API, Modern

       D. Modern, API

Ans : REST, API

Q.5 What is the upper limit of an index that can be defined in a cluster?

       A. There is no upper limit

       B. 1000

       C. 99

       D. 10000

Ans : There is no upper limit


Q.6 Near-Real-Time means __________.

       A. Exactly at the same time

       B. Few minutes of wait time

       C. Slight time lag

Ans : Slight time lag


ElasticSearch Raports multiple choice questions for experience

Q.7 A node is ___________.

       A. Machines having Elastic family

       B. A single server running the instance of Elastic search

       C. A group of clusters running the instance of Elastic search

       D. Servers combined together with instances of Elastic search

Ans : A single server running the instance of Elasticsearch


Q.8 A cluster is ____________.

       A. Servers connected with each other

       B. A collection of nodes

       C. Both the options

       D. None of the options

Ans : Both the options


Q.9 Replicas is a ___________

       A. Copy of the cluster

       B. Carbon copy of the data living in a shard

       C. Carbon copy of the Index

       D. Replacement of the Index

Ans : Carbon copy of the data living in a shard


Q.10 A Shard is the subdivision of the ____________

       A. Document

       B. Index

       C. Nodes

Ans : Index


Q.11 Can we use uppercase to describe an index name?

       A. Yes, we can

       B. No, we cannot

Ans : No, we cannot


Q.12 Elasticsearch ___________.

       A. Exposes complexity

       B. Hides complexity

Ans : Hides complexity


Q.13 Elasticsearch may have thousands of nodes.

       A. True

       B. False

Ans : True


Q.14 Elastic search is _____________.

       A. Partially scalable

B. Highly scalable

Ans : Highly scalable


Q.15 Elasticsearch is built on the top of __________.

       A. Lucene

       B. Elastic

       C. Python

       D. Java

Ans : Lucene


Q.16 Elasticsearch uses _________ as the response.

       A. JSON objects

       B. XML objects

       C. Java objects

       D. Avro objects

Ans : JSON objects


Q.17 Who is the key person for the development of Elasticsearch?

       A. Ryan Dahl

       B. James Gosling

       C. Shay Banon

       D. Guido van Rossum

Ans : Shay Banon

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Q.18 A document is a/an ________.

A. JSON object

       B. JavaScript

       C. XML object

Ans : JSON object


Q.19 Is a single node cluster possible? If yes, what would be its default name?

       A. Yes, Elasticsearch

       B. No, not possible

       C. Yes, External

       D. None of the options

Ans : Yes, Elasticsearch


Q.20 _________ is the default name given to a cluster.

       A. Elastic

       B. External

       C. Elastic search1

       D. Elasticsearch

Ans : Elasticsearch


Q.21 You can delete an Index using ________.

       A. SUDO -XDEL ‘localhost:9200/aliens?pretty&pretty’

       B. curl -XDELETE ‘localhost:9200/aliens?pretty&pretty’

       C. curl -XDEL ‘localhost:9200/aliens?pretty&pretty’

Ans : curl -XDELETE ‘localhost:9200/aliens?pretty&pretty’


Q.22 Elasticsearch is schemaless.

       A. True

       B. False

Ans : True

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ElasticSearch – Search Raptors Part II

Q.1 What is an API?

       A. Application Program Interference

       B. A set of defined methods of communication between several software programs

       C. Both the options

       D. None of the options

Ans : A set of defined methods of communication between several software programs


Q.2 What does the yellow state of a cluster mean?

       A. It means all the shards are assigned in the cluster

       B. It means any of the replica shard is not assigned

       C. It means any of the primary shard is not assigned

       D. All the options

Ans : It means any of the replica shard is not assigned


Q.3 Which analyzer returns the entire input string as a single token?

       A. Whitespace Analyzer

       B. Simple Analyzer

       C. Stop Analyzer

       D. Keyword Analyzer

Ans : Keyword Analyzer


Q.4 You can delete a document using _________.

       A. curl -XDELETE ‘localhost:9200/aliens/external/1’

       B. curl -XDELETE ‘localhost:9200/aliens/1’

Ans : curl -XDELETE ‘localhost:9200/aliens/external/1’


Q.5 There is a dedicated array type in Elasticsearch.

       A. True

       B. False

Ans : False


Q.6 You can remove a plugin using _______.

       A. sudo bin/elasticsearch-plugin remove

       B. sudo bin/elasticsearch-plugin remove [pluginname]

Ans : sudo bin/elasticsearch-plugin remove [pluginname]


Q.7 You can create an Index using ________.

       A. curl -XPUT ‘localhost:9200/exampleIndex’

       B. curl -XPUT ‘localhost:9200/exampleindex’

       C. Both the options

       D. None of the options

Ans : curl -XPUT ‘localhost:9200/exampleindex’


Q.8 You can check the cluster’s health using _________.

       A. curl -XGET ‘localhost:9200/_cat/health’

       B. curl -XGET ‘localhost:9200/_cat/health?v&pretty’

       C. Both the options

       D. None of the options

Ans : curl -XGET ‘localhost:9200/_cat/health?v&pretty’


Q.9 What of the following is/are the feature(s) of a Fingerprint analyzer?

       A. The input text is normalized

       B. The input text is sorted

       C. The input text is made lowercase

       D. All the options

Ans : All the options


Q.10 How many primary shards are created by default?

       A. 2

       B. 3

       C. 4

       D. 5

Ans : 5


Q.11 What do we use for ‘ in the text I’ve?

       A. \u0027

       B. \u0026

       C. \u0012

       D. \u0018

Ans : \u0027


Q.12 The following languages are supported by the language analyzer, except ________.

       A. Japanese

       B. Hindi

       C. Arabic

       D. English

Ans : Japanese


Q.13 Which is a plugin type in Elasticsearch?

       A. Core plugins

       B. Community contributed plugins

       C. Both the options

       D. None of the options

Ans : Both the options

Q.14 What are Term-based Search Queries?

       A. Queries that search for the exact term that is present within the inverted text.

       B. Queries that search for the nearby terms that are present within the inverted text.

Ans : Queries that search for the exact term that is present within the inverted text.


Q.15 Elasticsearch can automatically create the mapping if the case mapping is not defined.

       A. True

       B. False

Ans : True


Q.16 Documents can have inner objects.

       A. True

       B. False

Ans : True


Q.17 For what purpose is Query DSL used in Elasticsearch?

       A. For Request Body Type search

       B. Only for simple search

Ans : For Request Body Type search


Q.18 You can perform a URI search using ______.

       A. curl -XGET “localhost:9200/_search=lastname:perkins&pretty”

       B. curl -XGET “localhost:9200/_search?q=lastname:perkins&pretty”

Ans : curl -XGET “localhost:9200/_search?q=lastname:perkins&pretty”

Q.19 In range query, what does gte and lt mean?

       A. Greater than or less than

       B. Greater than or equal to

       C. Greater than or equal to/Less than

       D. Greater than/Less than

Ans : Greater than or equal to/Less than


Q.20 Bulk Retrieve is implemented using ________.

       A. multi-get API

       B. mget API

       C. Both the options

       D. None of the options

Ans : Both the options


Q.21 Prequerying each shard to fetch the term and document frequencies is done in ____________.

       A. DFS Query, then in Fetch

       B. Fetch

       C. Query

Ans : DFS Query, then in Fetch


Q.22 How can you perform a match_all?

       A. {
  “query”: {
    “match_all”: {}
  }
}

       B. {
  “query”: {
    “match_all”
  }
}

Ans : {
  “query”: {
    “match_all”: {}
  }
}

ElasticSearch – Search Raptors Part-III

 A. Hierarchy Tokenization

       B. Classical Tokenization

       C. Filtration

       D. Document Analysis

Ans : Classical Tokenization


Q.6 Every shard in the index is broadcasted with the query in the _______.

       A. Fetch phase

       B. Query phase

Ans : Query phase


Q.7 Bulk API in Elasticsearch enables us to perform ___________.

       A. Create or delete operations of a single document

       B. Multiple create or delete operations

Ans : Multiple create or delete operations


Q.8 What should you use to fetch a document?

       A. curl -XGET ‘localhost:9200/aliens/external/1’?pretty

       B. curl -XPUT ‘localhost:9200/aliens/external/1’?pretty

Ans : curl -XGET ‘localhost:9200/aliens/external/1’?pretty


Q.9 What is mapping in Elasticsearch?

       A. A process of storing and indexing a document and its fields

       B. A process of copying documents

       C. A backup process so that we always have uninterrupted service

Ans : A process of storing and indexing a document and its fields


Q.10 In the command: curl -XPUT ‘localhost:9200/aliens/external/1’ -d ‘{ “name”: “Kryption”}’ , which is the type?.

A. alien

       B. 1

       C. external

       D. None of the options

Ans : alien


Q.11 A mapping type contains ___________.

       A. Meta-fields

       B. Fields/properties

       C. Both the options

       D. None of the options

Ans : Both the options


Q.12 How many replica shards are created by default?

       A. 1

       B. 3

       C. 4

       D. 5

Ans : 5


Q.13 What does the _all field do?

       A. It comprises of a list of fields/properties and corresponding type/data types

       B. It splits the values of the big string to small keywords

       C. It concatenates the values of all the other fields to form one big string

       D. It routes a document to a particular shard

Ans : It concatenates the values of all the other fields to form one big string


Q.14 In a RESTful web service, requests to the resource URI evoke a response in _______.

       A. XML

       B. JSON

C. HTML

       D. Any of the options

Ans : Any of the options


Q.15 A text data type is used when ________.

       A. We want to index a field having full-text values

       B. A field with structured content is indexed

Ans : We want to index a field having full-text values


Q.16 An array is a complex data type.

       A. True

       B. False

Ans : True


Q.17 With pattern analyzer, __________.

       A. Texts are split into terms

       B. Texts are preserved from being split

Ans : Texts are split into terms


Q.18 The Keyword data type is used with _________.

       A. Unstructured content

       B. Structured content

Ans : Structured content


Q.19 What does pretty perform in CRUD commands?

A. Makes the response in readable form

       B. Makes the response more beautiful

       C. Both the options

       D. None of the options

Ans : Makes the response in readable form


Q.20 Apart from the Elasticsearch’s usability as a text search engine, it can also be used as a _________.

       A. Java development tool

       B. SQL tool

       C. Data storage tool

       D. JSON development tool

Ans : Data storage tool


Q.21 Which is the type in the command curl -XPUT ‘localhost:9200/aliens/external/1’ -d ‘{ “name”: “Kryption”}’?

       A. 1

       B. external

       C. alien

       D. None of the options

Ans : external


Q.22 Standard tokenizer implements __________.

       A. Grammar-based tokenization

       B. Keyword Token Filter

       C. Breaking text into terms whenever it encounters a character

       D. Keyword Repeat Token Filter

Ans : Grammar-based tokenization

Elasticsearch Albertosaurus Multiple Choice Questions and Answers Part – I

Q.1 What is the disk usage limit above which the shards are not assigned to the nodes by default?

       A. Greater than 85%

       B. Greater than 75%

       C. Greater than 95%

       D. Greater than 65%

Ans : Greater than 85%


Q.2 Most of the domains have started using Elasticsearch as _________

       A. It supports structured and unstructured search

       B. It is scalable

       C. It is open source

       D. All the options

Ans : All the options


Q.3 What is the need for tuning the performance of Elasticsearch?

       A. It speeds up indexing

       B. It speeds up searching

       C. Both the options

Ans : Both the options


Q.4 The following are reasons for node failure, except ___________

       A. Hardware failure

       B. Hypervisor failure

       C. Sudden increase in the search rate

       D. None of the options

Ans : None of the options

Q.5 Which of the following is an indication that the cluster is ideal?

       A. Cluster Status is not green

       B. Cluster Status is green

       C. Cluster Status is yellow

Ans : Cluster Status is green


Q.6 When all the data nodes are running low on disk space, then the solution is __________.

       A. To add more data nodes to the cluster

       B. To set a threshold alert

       C. None of the options

Ans : To add more data nodes to the cluster


Q.7 The cluster status is red if __________.

       A. A secondary shard is missing

       B. A primary shard is missing

       C. A primary shard is available

Ans : A primary shard is missing


Q.8 What is force merging related to?

       A. Reducing the number of segments per shard to enhance search performance

       B. Increasing the number of segments per shard to enhance search performance

Ans : Reducing the number of segments per shard to enhance search performance


Q.9 More than one node starts behaving as master node during the __________.

       A. Combined Brain syndrome

       B. Connected Brain syndrome

       C. Split Brain syndrome

       D. None of the options

Ans : Split Brain syndrome


Q.10 Force merging is advisable at ___________.

       A. Non-peak time

       B. Peak time

Ans : Non-peak time


Q.11 bootstrap.memory_lock: true _____________.

       A. Allows the swapping process

       B. Disallows the swapping process

Ans : Disallows the swapping process


Q.12 The following are types of nodes in Elasticsearch, except ________

       A. Data node

       B. Ingest node

       C. Customized node

       D. Master-eligible node

Ans : Customized node


Q.13 The cluster status is yellow if ___________.

       A. A replica shard is missing

       B. Both primary and replica shards are missing

       C. A primary shard is missing

Ans : A replica shard is missing


Q.14 CRUD operations are accomplished by ____________.

       A. Data node

       B. Ingest node

       C. Coordinating node

       D. Tribe node

Ans : Data node


Q.15 To avoid TOO_MANY_REQUESTS (429) response, ___________.

       A. Avoid using threads while indexing

       B. Use multiple threads while indexing

       C. Use single thread while indexing

Ans : Use multiple threads while indexing


Q.16 Searching and Indexing performance in Elasticsearch depends upon _________.

       A. Hardware

       B. The type of query

       C. The style of indexing

       D. All the options

Ans : All the options


Q.17 Copying a page of memory to a pre-configured space in the hard disk for freeing up the page of memory is called _____________.

       A. Debugging

       B. Swapping

       C. Swap space

Ans : Swapping


Q.18 What is the impact of split brain syndrome?

       A. Indexing requests to any of the nodes will result in adding data to both the shards.

       B. Indexing requests to any of the nodes will result in adding no data to any of the shards.

Ans : Indexing requests to any of the nodes will result in adding data to both the shards.

Q.19 Search operations on connected clusters is accomplished with the help of _______________.

       A. Tribe node

       B. Ingest node

Ans : Tribe node


Q.20 What hinders the performance and causes garbage collection to run for minutes?

       A. Debugging

       B. Swapping

       C. Swap space

Ans : Swapping

Elasticsearch Albertosaurus Multiple Choice Questions and Answers Part – II

Q.1 Why Elasticsearch is called scalable?

       A. Because it can handle high loads on the system easily

       B. Only because creating more shards and indices is easy

       C. None of the options

Ans : Because it can handle high loads on the system easily


Q.2 Settings of which Elasticsearch file can be tweaked to avoid split-brain as well as tune the performance?

       A. elasticsearch.xml

       B. elasticsearch.html

       C. elasticsearch.yml

       D. elasticsearch.json

Ans : elasticsearch.yml


Q.3 node.master is set to true for _____________.

       A. Master-eligible node

       B. Ingest node

       C. Data node

       D. None of the options

Ans : Master-eligible node


Q.4 Creating too many shards and indices __________.

       A. Affects the searching and indexing performance

       B. Does not put any effect on performance

Ans : Affects the searching and indexing performance


Q.5 SSD drives are preferred over spinning drives in terms of performance tuning.

       A. True

 B. False

Ans : True


Q.6 You can change the IP address to which the elasticsearch is bound in Elasticsearch.yml file.

       A. True

       B. False

Ans : True


Q.7 While returning large result sets, ensure the use of __________.

       A. Scroll API

       B. Search API

Ans : Scroll API


Q.8 When all the data nodes are running low on disk space then the solution is __________.

       A. A threshold alert can be set

       B. Adding more data nodes to the cluster

       C. None of the options

Ans : Adding more data nodes to the cluster


Q.9 Which of the following is an ideal RAM size for Elasticsearch on production scale?

       A. 2 GB

       B. 6 GB

       C. 16 GB

       D. 1 GB

Ans : 16 GB


Q.10 In Elasticsearch.yml file, under what name is node name represented?

       A. nodes.name

B. node.name

       C. name.node

       D. node.names

Ans : node.name


Q.11 Elasticsearch indexes and store data based on the __________.

       A. Cloud data structure

       B. Amazon data structure

       C. Lucene data-structure

Ans : Lucene data-structure


Q.12 There should be same version of JVM across the machines with Elasticsearch.

       A. True

       B. False

Ans : True


Q.13 All failed Elasticsearch nodes are automatically detected and replaced by the Amazon ES.

       A. Correct

       B. Incorrect

Ans : Correct


Q.14 Putting the cluster on public IP is recommended in Elasticsearch. Choose the relevant option.

       A. Yes, because it helps in securing the clusters.

       B. No, always avoid putting clusters on Public IP.

Ans : Yes, because it helps in securing the clusters.


Q.15 discovery.zen.minimum_master_nodes represents ___________.

       A. the numbers nodes in communication which would elect the data node.

       B. The number of nodes in communication which would elect the master node

Ans : The number of nodes in communication which would elect the master node

Q.16 The heap size of JVM is 4 GB at the time of starting the Elasticsearch.

       A. True

       B. False

Ans : False


Q.17 Use filters when possible and queries when you need the actual scoring from queries.

       A. True

       B. False

Ans : True


Q.18 It is always a bad idea to use different Index for different structures.

       A. Correct

       B. Incorrect

Ans : Correct


Q.19 Where is the cluster.name setting located?

       A. Within the cluster settings

       B. elasticsearch.yml file

       C. elasticsearch.xml file

       D. Within the node settings

Ans : elasticsearch.yml file


Q.20 What kind of disks are recommended for frequent and large indexing?

       A. CD/ DVDs

 B. SSDs

       C. Spinning disks with low RPM

       D. None of the options

Ans : SSDs


Q.21 Giving memory to filesystem cache ensures ___________.

       A. Pause search function

       B. Efficient search function

       C. Slow search function

Ans : Efficient search function

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