From 8a7c5c8375d61b1a4d35fa6777b476ab380d40bb Mon Sep 17 00:00:00 2001
From: Masashi Tomooka <tmokmss@users.noreply.github.com>
Date: Fri, 29 Mar 2024 08:15:43 +0900
Subject: [PATCH] chore(opensearchservice): t3 instance type does not support
 Multi-AZ with standby feature (#29607)

### Issue # (if applicable)
Related with #26026

### Reason for this change

#26082 enabled Multi-AZ with Standby by default, but deployment fails if we use t3 instance type, because it does not support the feature. To fail fast, this PR adds validation on synth time.

> Multi-AZ with Standby only works with the m5, c5, r5, r6g, c6g, m6g, r6gd and i3 instance types.
> https://docs.aws.amazon.com/opensearch-service/latest/developerguide/managedomains-multiaz.html

> You can use T3 instance types only if your domain is provisioned without standby.
> https://docs.aws.amazon.com/opensearch-service/latest/developerguide/supported-instance-types.html#latest-gen

### Description of changes

If the instance type of data node or master node is t3, throws an error.

I also considered to automatically set `multiAzWithStandbyEnabled: false` if we detect any t3 instance type, but it would introduce unwanted behavior e.g. in the below case:

```ts
// Initial state
// multiAzWithStandbyEnabled: true as there's no t3 instance type
 new Domain(stack, 'Domain', {
    version: engineVersion,
    capacity: {
      dataNodeInstanceType: 'r5.large.search',
    },
})

// Update domain to add master nodes with t3 instance type
new Domain(stack, 'Domain', {
    version: engineVersion,
    capacity: {
      dataNodeInstanceType: 'r5.large.search',
      masterNodeInstanceType: 't3.medium.search',
      masterNodes: 3,
    },
})

// multiAzWithStandbyEnabled suddenly become false!
```

so we just throw an error.

### Description of how you validated changes

Added some unit tests.

I also confirmed that it results in deployment error if we try to deploy with t3 instance type & `multiAzWithStandbyEnabled : true` for both data node and master node.

### Checklist
- [X] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*
---
 .../aws-opensearchservice/lib/domain.ts       |  4 ++++
 .../aws-opensearchservice/test/domain.test.ts | 21 +++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/packages/aws-cdk-lib/aws-opensearchservice/lib/domain.ts b/packages/aws-cdk-lib/aws-opensearchservice/lib/domain.ts
index 644ff8e3f50fc..c5092fe765818 100644
--- a/packages/aws-cdk-lib/aws-opensearchservice/lib/domain.ts
+++ b/packages/aws-cdk-lib/aws-opensearchservice/lib/domain.ts
@@ -1828,6 +1828,10 @@ export class Domain extends DomainBase implements IDomain, ec2.IConnectable {
       }
     }
 
+    if (isSomeInstanceType('t3') && multiAzWithStandbyEnabled) {
+      throw new Error('T3 instance type does not support Multi-AZ with standby feature.');
+    }
+
     const offPeakWindowEnabled = props.offPeakWindowEnabled ?? props.offPeakWindowStart !== undefined;
     if (offPeakWindowEnabled) {
       this.validateWindowStartTime(props.offPeakWindowStart);
diff --git a/packages/aws-cdk-lib/aws-opensearchservice/test/domain.test.ts b/packages/aws-cdk-lib/aws-opensearchservice/test/domain.test.ts
index 4c7796fe3e5ea..78bbc70afed30 100644
--- a/packages/aws-cdk-lib/aws-opensearchservice/test/domain.test.ts
+++ b/packages/aws-cdk-lib/aws-opensearchservice/test/domain.test.ts
@@ -408,6 +408,27 @@ each([testedOpenSearchVersions]).test('can specify multiAZWithStandbyEnabled in
   });
 });
 
+each([testedOpenSearchVersions]).test('multiAZWithStandbyEnabled: true throws with t3 instance type (data node)', (engineVersion) => {
+  expect(() => new Domain(stack, 'Domain', {
+    version: engineVersion,
+    capacity: {
+      dataNodeInstanceType: 't3.medium.search',
+      multiAzWithStandbyEnabled: true,
+    },
+  })).toThrow(/T3 instance type does not support Multi-AZ with standby feature\./);
+});
+
+each([testedOpenSearchVersions]).test('multiAZWithStandbyEnabled: true throws with t3 instance type (master node)', (engineVersion) => {
+  expect(() => new Domain(stack, 'Domain', {
+    version: engineVersion,
+    capacity: {
+      masterNodeInstanceType: 't3.medium.search',
+      masterNodes: 1,
+      multiAzWithStandbyEnabled: true,
+    },
+  })).toThrow(/T3 instance type does not support Multi-AZ with standby feature\./);
+});
+
 each([testedOpenSearchVersions]).test('ENABLE_OPENSEARCH_MULTIAZ_WITH_STANDBY set multiAZWithStandbyEnabled value', (engineVersion) => {
   const stackWithFlag = new Stack(app, 'StackWithFlag', {
     env: { account: '1234', region: 'testregion' },