feat(compute): add AWS Lambda MicroVMs ComputeStrategy backend — P1 (#645)

[dreamorosi]

Implements Phase P1 of ADR-021 (#688): the lambda-microvm compute backend — strategy (start/poll/stop), CDK infrastructure, bootstrap policy, CLI support, and layered regional-availability enforcement. AgentCore remains the default. Suspend/resume is P3; agent-side hook serving and smoke parity are P2 — the ADR and the construct both warn explicitly that a P1-built image is not runnable end to end.

Strategy reports, orchestrator interprets

LambdaMicrovmComputeStrategy.pollSession maps the six-state MicrovmState enum mechanically (SessionStatus gains 'suspended'); the orchestrator cross-references DynamoDB — substrate-terminal + non-terminal status → failed (with a confirm re-read to avoid failing a successful fast teardown), suspended + non-AWAITING_APPROVAL → anomaly event, no fail-fast. RunMicrovm always omits idlePolicy (auto-suspend disabled by construction, asserted by tests) and pins maximumDurationInSeconds at 28 800 s (AgentCore 8 h parity). Strategy errors carry a MicroVM <op> failed marker so the new classifier entries cannot change agentcore/ECS retry semantics — pinned by regression tests against the pre-change UNKNOWN shape.

No image wildcards in IAM

Every grant is scoped to the exact image ARN (bare names are resolved via formatArn; a ':*' sibling covers version-qualified forms — image names cannot contain :). microvmConfig.imageArn is compiler-required, so the account-wide fallback cannot return silently. Orchestrator gets exactly RunMicrovm/GetMicrovm/TerminateMicrovm/PassNetworkConnector + scoped iam:PassRole; the cancel Lambda gets TerminateMicrovm only; no Suspend/Resume/auth-token grants anywhere (P3), asserted by tests including on the generated bootstrap JSON.

Regional availability enforced in layers

Synth-time gate on the 5 launch regions with a microvm_region_override escape hatch (token regions skipped, documented); CLI onboarding probes ListManagedMicrovmImages on the effective compute type (flag ?? stored ?? default) before any write; platform doctor probes when an active blueprint uses the backend; orchestration-time classification is non-retryable with a configuration remedy.

Cancellation ordering fix worth reviewer attention

The new lambda-microvm branch in cancel-task.ts is deliberately placed before the agentRuntimeArn fallback: RUNTIME_ARN is set stack-wide whenever AgentCore stop is wired, so a MicroVM task would otherwise have invoked StopRuntimeSession against an unrelated runtime in mixed deployments. Pinned by a regression test.

ADR-021 refined in place (proposed): six-state poll-mapping table, GetMicrovm NotFound → completed rationale, microvmId/microvmIdentifier seam, per-hook phasing table.

Verification: cdk 141 suites / 2 744 tests, cli 52 / 651, tsc + eslint clean in both, types-sync green, knip at baseline (78), bootstrap generation and docs sync deterministic. DEPLOYMENT_ROLES.md gains golden policy block [5] with test parity.

Refs #645

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[dreamorosi]

I'll address the CI comments tomorrow

[krokoko]

Thanks for this — Phase P1 of ADR-021 is thoughtfully scoped, and the write-up makes the intentional non-goals (P2 hooks / P3 suspend) easy to review against. Strategy-vs-orchestrator split, image-ARN IAM scoping, cancel ordering before the RUNTIME_ARN fallback, and the layered regional gates all look solid. CI green + strong test coverage help a lot.

Request changes

Onboard should gate on ComputeSubstrate for lambda-microvm (parity with ECS)

In cli/src/commands/repo.ts, ECS already refuses onboard when the stack wasn’t deployed with the ECS substrate. MicroVM currently only probes regional availability (ListManagedMicrovmImages), so an operator can still write compute_type=lambda-microvm against an agentcore-only stack and only fail later at RunMicrovm.

Suggest mirroring the ECS check (and the onboard note) for lambda-microvm when ComputeSubstrate is present and not lambda-microvm. The agent stack already emits that output value.

Suggestions (non-blocking / nice-to-have in this PR)

1. microvm_suspend_anomaly spam — reconcileMicrovmSubstrateState emits on every poll (~30s) while suspended outside AWAITING_APPROVAL. Rare in P1 (no Suspend grants), but once it hits it can flood events for a long window. Emitting once per task (e.g. a PollState flag) would keep “no fail-fast” without the noise — especially useful before P3.

2. Orphan MicroVM if persist fails after RunMicrovm — start-session starts the VM, then writes compute_metadata; the catch path failTasks without TerminateMicrovm. Same race as AgentCore/ECS, but MicroVM cost/quota makes the leak more expensive. Best-effort terminate from the in-memory handle in the catch would close it. Fine as a follow-up issue if you’d rather not expand this PR.

3. Shared payload-bucket read — payloadBucket.grantRead(executionRole) is bucket-wide (incl. list), same shape as ECS #502. Scoping to the task key / dropping List* would improve isolation when this backend is enabled; also fine as follow-up.

4. Incomplete RunMicrovm response — the missing microvmId/endpoint throw isn’t wrapped with wrapMicrovmError, so it may miss the MicroVM classifier marker. Small consistency fix.

What looks great

• Exact 16 384 inline/S3 payload split, idlePolicy omitted, 28800s max duration
• Terminal substrate + DDB re-read before fail; suspend + approval treated as healthy
• No Suspend/Resume/auth-token grants; bootstrap deploy-time only with golden policy block
• Packaging script API shapes aligned with the service model
• Knip unexports are fine hygiene

Happy to re-review quickly once the onboard gate lands — and open to deferring 2–3 to tracked follow-ups if you prefer to keep this PR tight.