Add --instance-type-archs flag (#528)

kubetest2/internal/deployers/eksapi/deployer.go

@@ -67,7 +67,8 @@ type deployerOptions struct {
 	ExpectedAMI                 string   `flag:"expected-ami" desc:"Expected AMI of nodes. Up will fail if the actual nodes are not utilizing the expected AMI. Defaults to --ami if defined."`
 	// TODO: remove this once it's no longer used in downstream jobs
 	GenerateSSHKey      bool          `flag:"generate-ssh-key" desc:"Generate an SSH key to use for tests. The generated key should not be used in production, as it will not have a passphrase."`
-	InstanceTypes       []string      `flag:"instance-types" desc:"Node instance types"`
+	InstanceTypes       []string      `flag:"instance-types" desc:"Node instance types. Cannot be used with --instance-type-archs"`
+	InstanceTypeArchs   []string      `flag:"instance-type-archs" desc:"Use default node instance types for specific architectures. Cannot be used with --instance-types"`
 	IPFamily            string        `flag:"ip-family" desc:"IP family for the cluster (ipv4 or ipv6)"`
 	KubeconfigPath      string        `flag:"kubeconfig" desc:"Path to kubeconfig"`
 	KubernetesVersion   string        `flag:"kubernetes-version" desc:"cluster Kubernetes version"`
@@ -259,6 +260,9 @@ func (d *deployer) verifyUpFlags() error {
 		klog.Infof("Skip configuration for static cluster")
 		return nil
 	}
+	if len(d.InstanceTypes) > 0 && len(d.InstanceTypeArchs) > 0 {
+		return fmt.Errorf("--instance-types and --instance-type-archs are mutually exclusive")
+	}
 	if d.UnmanagedNodes {
 		if d.AMI == "" {
 			return fmt.Errorf("--ami must be specified for --unmanaged-nodes")

kubetest2/internal/deployers/eksapi/node.go

@@ -99,7 +99,17 @@ func (m *nodeManager) createNodes(infra *Infrastructure, cluster *Cluster, opts
 func (m *nodeManager) resolveInstanceTypes(opts *deployerOptions) (err error) {
 	instanceTypes := opts.InstanceTypes
 	if len(instanceTypes) == 0 {
-		if opts.UnmanagedNodes {
+
+		if len(opts.InstanceTypeArchs) > 0 {
+			klog.Infof("choosing instance types based on architecture(s): %v", opts.InstanceTypeArchs)
+			for _, arch := range opts.InstanceTypeArchs {
+				instanceTypesForArch, ok := defaultInstanceTypesByEC2ArchitectureValues[ec2types.ArchitectureValues(arch)]
+				if !ok {
+					return fmt.Errorf("no default instance types known for architecture: '%s'", arch)
+				}
+				instanceTypes = append(instanceTypes, instanceTypesForArch...)
+			}
+		} else if opts.UnmanagedNodes {
 			klog.Infof("choosing instance types based on AMI architecture...")
 			if out, err := m.clients.EC2().DescribeImages(context.TODO(), &ec2.DescribeImagesInput{
 				ImageIds: []string{opts.AMI},