feat: karpenter allows on-demand instances TDE-1185 (#622)

#### Motivation

Karpenter should allow on-demand instances.

#### Modification

Add `on-demand` in the list of requirements capacity types.

#### Checklist

- [x] Tests updated Tested on nonprod cluster
- [ ] Docs updated
- [x] Issue linked in Title

infra/charts/karpenter.ts

@@ -122,7 +122,7 @@ export class KarpenterProvisioner extends Chart {
       },
     });
 
-    const provisionAmd64 = new Provisioner(this, 'ClusterAmd64WorkerNodes', {
+    const provisionAmd64Spot = new Provisioner(this, 'ClusterAmd64WorkerNodesSpot', {
       metadata: { name: `karpenter-amd64-spot`, namespace: 'karpenter' },
       spec: {
         // Ensure only pods that tolerate spot run on spot instance types
@@ -139,6 +139,20 @@ export class KarpenterProvisioner extends Chart {
       },
     });
 
+    const provisionAmd64OnDemand = new Provisioner(this, 'ClusterAmd64WorkerNodesOnDemand', {
+      metadata: { name: `karpenter-amd64-on-demand`, namespace: 'karpenter' },
+      spec: {
+        requirements: [
+          { key: 'karpenter.sh/capacity-type', operator: 'In', values: ['on-demand'] },
+          { key: 'kubernetes.io/arch', operator: 'In', values: ['amd64'] },
+          { key: 'karpenter.k8s.aws/instance-family', operator: 'In', values: ['c5', 'c6i', 'c6a'] },
+        ],
+        limits: { resources: { cpu: ProvisionerSpecLimitsResources.fromNumber(2000) } },
+        providerRef: { ...AwsNodeTemplate.GVK, name: templateName },
+        ttlSecondsAfterEmpty: Duration.minutes(1).toSeconds(), // optional, but never scales down if not set
+      },
+    });
+
     const provisionArm64 = new Provisioner(this, 'ClusterArmWorkerNodes', {
       metadata: { name: `karpenter-arm64-spot`, namespace: 'karpenter' },
       spec: {
@@ -161,7 +175,8 @@ export class KarpenterProvisioner extends Chart {
       },
     });
 
-    provisionAmd64.node.addDependency(template);
+    provisionAmd64Spot.node.addDependency(template);
+    provisionAmd64OnDemand.node.addDependency(template);
     provisionArm64.node.addDependency(template);
   }
 }