Elasticsearch Interview Questions and Answers
Freshers / Beginner level questions & answers
Ques 1. What is Elasticsearch?
Elasticsearch is a distributed search and analytics engine built on top of Apache Lucene.
Ques 2. Explain the term 'Index' in Elasticsearch.
An index in Elasticsearch is a collection of documents that share a similar structure and are stored together for efficient searching.
Ques 3. What is a Document in Elasticsearch?
A document is the basic unit of information in Elasticsearch, represented in JSON format.
Ques 4. Explain the purpose of the 'Cluster' in Elasticsearch.
A cluster is a collection of nodes that work together and share the same cluster name, forming a single logical unit.
Ques 5. What is the role of a 'Node' in Elasticsearch?
A node is a single instance of Elasticsearch running within a cluster, storing data and participating in cluster operations.
Ques 6. Explain the concept of 'Tokenization' in Elasticsearch.
Tokenization is the process of breaking a text into individual terms or tokens, which become searchable in Elasticsearch.
Ques 7. What is the purpose of the 'Refresh' operation in Elasticsearch?
Refresh makes changes to the index immediately visible for search, but it comes with a performance cost.
Ques 8. Explain the role of 'Filter' in Elasticsearch queries.
Filters are used to narrow down the search results based on specific criteria without affecting scoring.
Ques 9. Explain the term 'Bulk API' in Elasticsearch.
The Bulk API allows for the efficient indexing and deletion of multiple documents in a single request.
Ques 10. What is the purpose of the 'CAT API' in Elasticsearch?
The CAT API provides concise information about the cluster, indices, and nodes in a human-readable format.
Ques 11. What is Elasticsearch?
Elasticsearch is a distributed search and analytics engine built on top of Apache Lucene. It provides a scalable and real-time search solution.
Example:
GET /index/_search?q=query
Ques 12. What is a 'Node' in Elasticsearch?
A node is a single instance of Elasticsearch running on a machine. It is part of a cluster and stores data and participates in the indexing and search capabilities of Elasticsearch.
Example:
GET /_cat/nodes?v
Ques 13. What is the role of the 'Cat' API in Elasticsearch?
The 'Cat' API in Elasticsearch provides concise and human-readable information about the cluster, nodes, indices, and other components. It is useful for monitoring and debugging.
Example:
GET /_cat/indices?v
Ques 14. What is the purpose of the 'Cluster Health' API in Elasticsearch?
The 'Cluster Health' API provides information about the overall health of the Elasticsearch cluster, including the status of nodes, indices, and other vital statistics.
Example:
GET /_cluster/health
Ques 15. How can you limit the number of results in an Elasticsearch query?
You can use the 'size' parameter in your query to limit the number of results returned. For example, 'size': 10 will return only 10 documents.
Example:
GET /my_index/_search
{
"query": {
"match_all": {}
},
"size": 10
}
Most helpful rated by users: