Comparing OpenSearch Service and OpenSearch Serverless

In OpenSearch Serverless, some concepts and features are different than their corresponding feature for a provisioned OpenSearch Service domain. For example, one important difference is that OpenSearch Serverless doesn't have the concept of a cluster or node.

The following table describes how important features and concepts in OpenSearch Serverless differ from the equivalent feature in a provisioned OpenSearch Service domain.

Feature	OpenSearch Service	OpenSearch Serverless
Domains versus collections	Indexes are held in domains, which are pre-provisioned OpenSearch clusters. For more information, see Creating and managing Amazon OpenSearch Service domains.	Indexes are held in collections, which are logical groupings of indexes that represent a specific workload or use case. For more information, see Creating, listing, and deleting Amazon OpenSearch Serverless collections.
Node types and capacity management	You build a cluster with node types that meet your cost and performance specifications. You must calculate your own storage requirements and choose an instance type for your domain. For more information, see Sizing Amazon OpenSearch Service domains.	OpenSearch Serverless automatically scales and provisions additional compute units for your account based on your capacity usage. For more information, see Managing capacity limits for Amazon OpenSearch Serverless.
Billing	You pay for each hour of use of an EC2 instance and for the cumulative size of any EBS storage volumes attached to your instances. For more information, see Pricing for Amazon OpenSearch Service.	You're charged in OCU-hours for compute for data ingestion, compute for search and query, and storage retained in S3. For more information, see Pricing for OpenSearch Serverless.
Encryption	Encryption at rest is optional for domains. For more information, see Encryption of data at rest for Amazon OpenSearch Service.	Encryption at rest is required for collections. For more information, see Encryption in Amazon OpenSearch Serverless.
Data access control	Access to the data within domains is determined by IAM policies and fine-grained access control.	Access to data within collections is determined by data access policies.
Supported OpenSearch operations	OpenSearch Service supports a subset of all of the OpenSearch API operations. For more information, see Supported operations in Amazon OpenSearch Service.	OpenSearch Serverless supports a different subset of OpenSearch API operations. For more information, see Supported operations and plugins in Amazon OpenSearch Serverless.
Dashboards sign-in	Sign in with a username and password. For more information, see Accessing OpenSearch Dashboards as the master user.	If you're logged into the AWS console and navigate to your Dashboard URL, you'll automatically log in. For more information, see Accessing OpenSearch Dashboards.
APIs	Interact programmatically with OpenSearch Service using the OpenSearch Service API operations.	Interact programmatically with OpenSearch Serverless using the OpenSearch Serverless API operations.
Network access	Network settings for a domain apply to the domain endpoint as well as the OpenSearch Dashboards endpoint. Network access for both is tightly coupled.	Network settings for the domain endpoint and the OpenSearch Dashboards endpoint are decoupled. You can choose to not configure network access for OpenSearch Dashboards. For more information, see Network access for Amazon OpenSearch Serverless.
Signing requests	Use the OpenSearch high and low-level REST clients to sign requests. Specify the service name as es.	At this time, OpenSearch Serverless supports a subset of clients that OpenSearch Service supports. When you sign requests, specify the service name as aoss. The x-amz-content-sha256 header is required. For more information, see Signing HTTP requests with other clients.
OpenSearch version upgrades	You manually upgrade your domains as new versions of OpenSearch become available. You're responsible for ensuring that your domain meets the upgrade requirements, and that you've addressed any breaking changes.	OpenSearch Serverless automatically upgrades your collections to new OpenSearch versions. Upgrades don't necessarily happen as soon as a new version is available.
Service software updates	You manually apply service software updates to your domain as they become available.	OpenSearch Serverless automatically updates your collections to consume the latest bug fixes, features, and performance improvements.
VPC access	You can provision your domain within a VPC. You can also create additional OpenSearch Service-managed VPC endpoints to access the domain.	You create one or more OpenSearch Serverless-managed VPC endpoints for your account. Then, you include these endpoints within network policies.
SAML authentication	You enable SAML authentication on a per-domain basis. For more information, see SAML authentication for OpenSearch Dashboards.	You configure one or more SAML providers at the account level, then you include the associated user and group IDs within data access policies. For more information, see SAML authentication for Amazon OpenSearch Serverless.
Transport Layer Security (TLS)	OpenSearch Service supports TLS 1.2 but it is recommend you use TLS 1.3.	OpenSearch Serverless supports TLS 1.2 but it is recommended you use TLS 1.3.