Difficulty: Easy
Description
We identified several OpenSearch instances in your account that are using older generation instance types. Modernizing these instances can help reduce your OpenSearch bill.
Selection Criteria
The OpenSearch node uses an older generation instance family (e.g.
r5,m5,c5,t3,i3) and a newer generation equivalent is available (r6g,r7g,m6g,m7g,c6g,c7g,t4g,i4g).A newer instance type in the same family and size is available in the domain's region.
The modernized target yields positive savings after applying the existing Reserved Instance discount (if any).
⚠️ Warning — Reserved Instances: changing the instance family invalidates the RI coverage for that node. Verify RI scope and remaining term before proceeding.
Expected Saving
Modernizing OpenSearch instances typically yields 10–25% savings per node on compute costs. The exact amount depends on the target family, existing Reserved Instance coverage, and the distributor discount applied.
Upgrade path | Example | Typical savings |
Same arch, newer gen ( |
| ~14% |
Latest Graviton gen ( |
| ~20% |
Latest Graviton gen ( |
| ~15–20% |
Example — OpenSearch domain with 3 × r5.large.search nodes (1yr RI All-Upfront, 20% distributor discount):
Current effective cost: ~$0.233/hr × 8 760 hrs = $2 041/node/year
Upgraded to
r7g.large.search: ~$0.184/hr × 8 760 hrs = $1 613/node/yearSavings: ~$428/node/year (~21%) → ~$1 284/year for the 3-node domain
⚠️ When an RI covers the current node, the same distributor discount is projected on the target instance price to avoid showing artificial negative savings.
Operational Impact
Blue/green deployment: OpenSearch Service performs instance type changes via a blue/green deployment. No customer-visible downtime on Multi-AZ domains — shards are replicated to the new nodes before traffic is switched.
Duration: can take several hours on large domains (data must be re-indexed on the new nodes). The domain is in "Processing" state during the migration.
Temporary capacity usage: during blue/green, AWS provisions the target nodes in parallel with the existing ones — temporary doubling of nodes counts toward service quotas.
⚠️ Reserved Instances: changing the instance family leaves the original RI stranded (it continues billing on the old family until expiration). Consider the RI remaining term before proceeding, or align the change with RI expiration.
Recovery: revert to the previous instance type via another modification — no data loss, but another blue/green cycle is required.