Amazon OpenSearch Serverless
OpenSearch without managing clusters
The serverless version of OpenSearch: you create a collection (search, time series, or vector search), and AWS automatically scales compute capacity, measured in OCUs (OpenSearch Compute Units), for indexing and queries.
- Cost$$ Medium
- Difficulty●●●●●
- Costs money when idle?Yes
- Serverless
- In examsSAA
Think of it asLike an all-inclusive library service: you just bring the books and look things up, without worrying about shelves, staff, or expanding the room.
When to use it
✓ Use it when
You need full-text search, log analytics, or a vector store for RAG without managing a cluster.
✗ Avoid it when
Small, steady workloads, cost optimization, or deep cluster tuning → OpenSearch Service (managed cluster).
Common uses
- Vector store for Bedrock Knowledge Bases
- Full-text product search
- Time-based log analytics
What does it cost?
- Pricing model: Charged per OCU-hour for indexing and search, plus GB of data stored on S3 per month.
⚠️ Cost traps
The minimum OCUs are still billed when a collection has no load; many collections with different encryption keys can increase the OCU count.
