ElasticSearch ElasticSearch MCQ 4 — Questions and Answers
Question 1: Which Elasticsearch mechanism automatically moves shards between nodes to balance disk usage and load?
- Shard allocation awareness
- Cluster reroute API
- Automatic shard rebalancing (Correct answer)
- Shrink API
Correct answer: Automatic shard rebalancing
Elasticsearch automatically rebalances shards across nodes to maintain an even distribution of data and load when nodes join or leave the cluster.
Question 2: What does the '_source' field in an Elasticsearch document contain?
- Only the indexed fields used for search
- The original JSON document body as provided at index time (Correct answer)
- The Lucene segment metadata
- The routing hash for shard assignment
Correct answer: The original JSON document body as provided at index time
The _source field stores the original JSON document exactly as it was indexed, enabling retrieval and partial updates without re-indexing.
Question 3: Which Elasticsearch query type allows you to find documents where a field value falls between a minimum and maximum value?
- match
- term
- range (Correct answer)
- prefix
Correct answer: range
The range query finds documents where a field value falls within specified bounds using operators like gte, lte, gt, and lt.
Question 4: What is a 'hot-warm' architecture in Elasticsearch used for?
- Separating real-time indexing nodes from nodes holding older, less-queried data (Correct answer)
- Separating master nodes from data nodes
- Balancing read and write traffic across the cluster
- Routing queries to geographically closer nodes
Correct answer: Separating real-time indexing nodes from nodes holding older, less-queried data
A hot-warm architecture uses high-performance 'hot' nodes for recent active data and cheaper 'warm' nodes for older, infrequently accessed historical data.
Question 5: Which Elasticsearch feature allows you to automatically roll over to a new index when an index reaches a certain size, document count, or age?
- Shrink API
- Rollover API (Correct answer)
- Reindex API
- Split API
Correct answer: Rollover API
The Rollover API creates a new index for a data stream or index alias when the current index reaches configured thresholds like max_age, max_docs, or max_size.
Question 6: In Elasticsearch, what does the 'should' clause in a bool query do when no 'must' or 'filter' clauses are present?
- Acts as a required condition; documents must match at least one should clause (Correct answer)
- Documents matching should clauses receive a boost but no minimum match is required
- Should clauses are completely ignored in scoring
- Should clauses are treated identically to filter clauses
Correct answer: Acts as a required condition; documents must match at least one should clause
When a bool query contains only 'should' clauses (no must/filter), at least one should clause must match, controlled by minimum_should_match (defaults to 1).
Question 7: Which Elasticsearch API can you use to check the health of a cluster and get a color-coded status?
- _stats API
- _cluster/health API (Correct answer)
- _nodes/stats API
- _cat/indices API
Correct answer: _cluster/health API
The _cluster/health API returns the cluster's health status as green (all shards assigned), yellow (all primaries assigned, some replicas unassigned), or red (some primaries unassigned).
ElasticSearch ElasticSearch MCQ 4
Which Elasticsearch mechanism automatically moves shards between nodes to balance disk usage and load?