Elastic Security Analytics Interview Questions and Answers

Q1. What is Elasticsearch?

Ans

Elasticsearch is a NoSQL database. It is based on the Lucene search engine, and it is built with RESTful APIS. It offers simple deployment, maximum reliability, and easy management. It also provides advanced queries to perform detailed analysis and stores all the data centrally. It helps execute a quick search of the documents.

Q2. What are the important features of Elasticsearch?

Ans

• An open-source search server written using Java.
• Used to index any kind of heterogeneous data
• Has REST API web-interface with JSON output
• Full-Text Search
• Near Real-Time (NRT) search
• Sharded, replicated searchable, JSON document store.
• Schema-free, REST & JSON based distributed document store
• Multi-language & Geolocation support

Q3. What is a document in Elastic Search?

Ans

In an Elastic search, a document is a basic unit of information that can be indexed. It is expressed in JSON (key: value) pair. ‘{“user”: “nullcon”}’. Every single Document is associated with a type and a unique id.

Q4. Define the Term Shard

Ans

Every index can be split into several shards to be able to distribute data. The shard is the atomic part of an index, which can be distributed over the cluster if you want to add more nodes.

Q5. What are the important advantages of Elastic Search?

Ans

• Store schema-less data and also creates a schema for your data.
• Manipulate your data record by record with the help of Multi-document APIs
• Perform filtering and querying your data for insights
• Based on Apache Lucene and provides RESTful API
• It provides horizontal scalability, reliability, and multitenant capability for real-time use of indexing.
• Helps you to scale vertically and horizontally

Q6. What is the ELK stack?

Ans

The ELK Stack is a collection of three open-source products — Elasticsearch, Logstash, and Kibana. They are all developed, managed, and maintained by the company Elastic.

• E stands for ElasticSearch: It is used for storing logs.
• L stands for LogStash: It is used for both shipping as well as the processing and storing logs.
• K stands for Kibana: It is a visualization tool (a web interface) that is hosted through Nginx or Apache.

Q7. Explain Tokenizer in ElasticSearch

Ans

A Tokenizer breakdown fields which values of a document into a stream. Inverted indexes are created and updated by using these values. After that, these stream of values are stored in the document.

Q8. What Are The Main Operations You Can Perform On A Document?

Ans

• Indexing a document
• Fetching documents
• Updating documents
• Deleting documents

Q9. What is Mapping?

Ans

Mapping is a process that helps you define how a document is mapped to the search engine. Its searchable characteristics are included fields are tokenized as well as searchable.

Q10. What is Apache Lucene?

Ans

Apache Lucene is an open-source information retrieval software library. It is originally written in Java language.

Q11. What is NRT in Elasticsearch?

Ans

NRT is a full form of (Near Real-Time Search) platform. It is a near real-time search platform. It means there is a slight latency (mostly one second) from when you index a document until it becomes very searchable.

Q12. What are the various commands available in Elasticsearch cat API?

Ans

• Cat aliases, cat allocation, cat count, cat fielddata
• Cat health, cat indices, cat master, pending tasks, cat plugins, cat recovery
• cat repositories, cat snapshots, cat templates

Q13. What is Ingest node?

Ans

Ingest node is use for pre-process documents before the actual document indexing happens. It helps you to intercepts bulk and index requests. It also applies transformations, and then it passes the documents back to the bulk API and index.

Q14. What are the various ways of using X-Pack Commands?

Ans

• Certgen
• migrate
• syskeygen
• certutil
• saml-metadata
• setup-passwords
• users

Q15. What are Aggregations?

Ans

The aggregations framework helps you to provide aggregated data based on a search query. It is based on simple building blocks known as aggregations. It can be composed to build complex summaries of the data.

Q16. What is Query DSL in Elasticsearch?

Ans

Elasticsearch offers full Query DSL (Domain Specific Language) based on JSON to define queries.

Q17. What is Elasticsearch Data Node?

Ans

Data nodes hold shards that handle indexed documents. They help you to execute data related CRUD and search aggregation operations etc. However, you need to Set node.data=true to make node as Data Node.

Q18. What is dynamic mapping in Elasticsearch?

Ans

Dynamic mapping helps the user to index documents without unwanted configurations for the field name. Instead, it will be added automatically through the Elasticsearch with some custom rules.

Q19. What is fuzzy search Elasticsearch?

Ans

Fuzzy search is a process in which web page document locations should be identified. That is resembling with the search argument. It also works when the argument is not relevant to the search correspondent for particular information.