[FEATURE] Support Optimized Engine (AWS Deploy)

[jagadishkumar12]

What solution would you like?

For the deploy to AWS option, requesting support for the new Optimized Engine as an option when creating a domain.

[kylehounslow]

Initial triage — performed by an AI agent, verified against source at release/v0.2.0 and the AWS OpenSearch docs (OR1 optimized instances).

What "Optimized Engine" maps to

"Optimized Engine" = OpenSearch optimized instances (OR1 / OR2 / OM2 / OI2 families) in AWS managed OpenSearch. There is no separate engine flag. It is selected entirely by the InstanceType value (e.g. or1.2xlarge.search) passed to CreateDomain / ClusterConfig.

Current state

• CLI takes instance type as free-text (aws/cli-installer/src/interactive.mjs:245) with a --os-instance-type flag (aws/cli-installer/src/cli.mjs:50). An OR1/OR2/OM2 type entered here already reaches CreateDomainCommand (aws/cli-installer/src/aws.mjs:236). Default is r6g.large.search — a standard, non-optimized type (config.mjs:9).
• Encryption at rest is already enabled (aws.mjs), and the default engine is OpenSearch_3.5 — both satisfy OR1 prerequisites (encryption required; new domains need >= 2.11).

Constraints (from AWS docs)

1. OI2 uses local NVMe storage and takes no EBS configuration. OR1/OR2/OM2 use gp3/io1 EBS. Both the CLI (aws.mjs:238-242) and CDK (aws/cdk/lib/opensearch.ts:37-40) send EBSOptions unconditionally, which conflicts with OI2.
2. Migrating an existing domain to OR1 is irreversible. Applies only to the create path; the "reuse existing domain" path cannot change it.
3. If dedicated master nodes are enabled, they must be Graviton. Neither the CLI nor CDK configures dedicated masters today, so no conflict, but any future master-node option must enforce this alongside optimized instances.

Actionable items

CLI — highest priority

1. aws/cli-installer/src/aws.mjs:238-242 — make EBSOptions conditional: omit it for OI2 (NVMe); keep gp3 for OR1/OR2/OM2 and standard types. This is a correctness fix, not just UX.
2. aws/cli-installer/src/interactive.mjs (stepOpenSearch, instance-type prompt at line 245) — add an instance-family selector (standard vs. optimized) and offer OR1/OR2/OM2/OI2 sizes, instead of relying on free-text entry.
3. aws/cli-installer/src/config.mjs (validateConfig) — add family-aware validation: optimized families require encryption at rest (already on) and engine >= 2.11 (default 3.5 satisfies); reject an OI2 type combined with an explicit EBS volume size.
4. config.mjs:9 — decide whether to keep r6g.large.search as the default or document optimized instances as recommended for log-analytics/observability workloads. No flag change needed; --os-instance-type already covers non-interactive use.

CDK — keep in sync

5. aws/cdk/lib/opensearch.ts:37-40 — same conditional-EBSOptions fix for OI2.
6. aws/cdk/lib/infra-stack.ts:44 — default r6g.large.search; expose optimized types as an option consistent with the CLI.

Terraform

Out of scope. terraform/aws/ runs self-hosted OpenSearch on EKS pods, not AWS managed OpenSearch, so instance-family selection does not apply.