feat(aws-eks): allow the use of graviton3 processors (#20543)

feat: allow the use of graviton3, 7th generation processors

fixes: #20482

----

### All Submissions:

* [x] Have you followed the guidelines in our [Contributing guide?](https://github.com/aws/aws-cdk/blob/master/CONTRIBUTING.md)

### Adding new Unconventional Dependencies:

* [ ] This PR adds new unconventional dependencies following the process described [here](https://github.com/aws/aws-cdk/blob/master/CONTRIBUTING.md/#adding-new-unconventional-dependencies)

### New Features

* [ ] Have you added the new feature to an [integration test](https://github.com/aws/aws-cdk/blob/master/INTEGRATION_TESTS.md)?
	* [ ] Did you use `yarn integ` to deploy the infrastructure and generate the snapshot (i.e. `yarn integ` without `--dry-run`)?

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/aws-eks/README.md

@@ -305,6 +305,7 @@ You may specify one `instanceType` in the launch template or multiple `instanceT
 > For more details visit [Launch Template Support](https://docs.aws.amazon.com/eks/latest/userguide/launch-templates.html).
 
 Graviton 2 instance types are supported including `c6g`, `m6g`, `r6g` and `t4g`.
+Graviton 3 instance types are supported including `c7g`.
 
 ### Fargate profiles
 

packages/@aws-cdk/aws-eks/lib/cluster.ts

@@ -2280,8 +2280,9 @@ function nodeTypeForInstanceType(instanceType: ec2.InstanceType) {
 
 function cpuArchForInstanceType(instanceType: ec2.InstanceType) {
   return INSTANCE_TYPES.graviton2.includes(instanceType.toString().substring(0, 3)) ? CpuArch.ARM_64 :
-    INSTANCE_TYPES.graviton.includes(instanceType.toString().substring(0, 2)) ? CpuArch.ARM_64 :
-      CpuArch.X86_64;
+    INSTANCE_TYPES.graviton3.includes(instanceType.toString().substring(0, 3)) ? CpuArch.ARM_64 :
+      INSTANCE_TYPES.graviton.includes(instanceType.toString().substring(0, 2)) ? CpuArch.ARM_64 :
+        CpuArch.X86_64;
 }
 
 function flatten<A>(xss: A[][]): A[] {

packages/@aws-cdk/aws-eks/lib/instance-types.ts

@@ -3,4 +3,5 @@ export const INSTANCE_TYPES = {
   inferentia: ['inf1'],
   graviton: ['a1'],
   graviton2: ['c6g', 'm6g', 'r6g', 't4g'],
+  graviton3: ['c7g'],
 };

packages/@aws-cdk/aws-eks/test/cluster.test.ts

@@ -1776,6 +1776,50 @@ describe('cluster', () => {
 
     });
 
+    test('addNodegroupCapacity with C7g instance type comes with nodegroup with correct AmiType', () => {
+      // GIVEN
+      const { stack } = testFixtureNoVpc();
+
+      // WHEN
+      new eks.Cluster(stack, 'cluster', {
+        defaultCapacity: 0,
+        version: CLUSTER_VERSION,
+        prune: false,
+        defaultCapacityInstance: new ec2.InstanceType('c7g.large'),
+      }).addNodegroupCapacity('ng', {
+        instanceTypes: [new ec2.InstanceType('c7g.large')],
+      });
+
+      // THEN
+      Template.fromStack(stack).hasResourceProperties('AWS::EKS::Nodegroup', {
+        AmiType: 'AL2_ARM_64',
+      });
+
+    });
+
+    test('addAutoScalingGroupCapacity with C7g instance type comes with nodegroup with correct AmiType', () => {
+      // GIVEN
+      const { app, stack } = testFixtureNoVpc();
+
+      // WHEN
+      new eks.Cluster(stack, 'cluster', {
+        defaultCapacity: 0,
+        version: CLUSTER_VERSION,
+        prune: false,
+      }).addAutoScalingGroupCapacity('ng', {
+        instanceType: new ec2.InstanceType('c7g.large'),
+      });
+
+      // THEN
+      const assembly = app.synth();
+      const parameters = assembly.getStackByName(stack.stackName).template.Parameters;
+      expect(Object.entries(parameters).some(
+        ([k, v]) => k.startsWith('SsmParameterValueawsserviceeksoptimizedami') &&
+          (v as any).Default.includes('amazon-linux-2-arm64/'),
+      )).toEqual(true);
+
+    });
+
     test('EKS-Optimized AMI with GPU support when addAutoScalingGroupCapacity', () => {
       // GIVEN
       const { app, stack } = testFixtureNoVpc();