# Amazon OpenSearch Service Domain

> An OpenSearch domain bills per instance-hour for every data and master node plus per GB-month of EBS storage, with no stop operation: a domain bills 24/7 until resized or deleted. ZopNight keeps 90 days of domain metrics and recommends rightsizing, storage tiering, and Graviton instance families.

Source: https://zop.dev/integrations/aws/opensearch
Updated: 2026-08-19

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Amazon OpenSearch Service runs managed OpenSearch and Elasticsearch domains billed per instance-hour plus storage. Search and logging domains are provisioned for peak indexing and rarely resized, making them consistent rightsizing candidates.

## Node-hours with no off switch

An OpenSearch domain bills per instance-hour for every node, whether data, dedicated master, or UltraWarm, plus per GB-month for its EBS-backed storage. There is no stop operation: a domain runs until it is reconfigured or deleted, which puts OpenSearch alongside ElastiCache as always-on by construction. Cost control here is entirely capacity control.

## Sized for the worst indexing day

Search and logging domains get provisioned for a peak: the migration backfill, the traffic spike, the holiday season. Then they stay there, because resizing a live search cluster feels risky. Months later the domain idles at low CPU with a node count nobody can justify. Dedicated master nodes on small dev domains and older non-Graviton instance families add their own quiet padding to the hourly total.

## Storage tiers exist here too

Hot EBS storage on data nodes is the expensive default. UltraWarm and cold storage hold older, rarely queried indices at much lower per-GB rates. This is the OpenSearch equivalent of S3 lifecycle tiering, and just as commonly left unconfigured on log-retention domains where most indices are never queried again after their first week.

## Watching without a stop verb

Domains are discovered on the 6-hour cycle. Hourly CloudWatch metrics from the OpenSearch namespace run with a 90-day lookback, and per-domain cost comes from Cost Explorer or CUR 2.0. Recommendations cover node rightsizing, storage tiering, and Graviton families; there is no scheduling, because there is nothing to stop.

## Domain details in the console

OpenSearch Service console, then Domains. A domain's Cluster configuration tab lists node counts and types per tier, the complete set of hourly meters in one table.