[feat][kubectl-plugin] add get workergroup cmd (ray-project#2996)

We plan to add a [command to scale a worker group][1] in an existing
RayCluster, e.g. `kubectl ray scale cluster (CLUSTER_NAME) (WORKER_GROUP)`. This
requires the user to know the group name. There's currently no way to get the
worker group names in a RayCluster other than getting the resource with kubectl
and looking for or parsing out the names. A command to get worker groups
details for a cluster might be helpful.

## Example Usage

```console
$ kubectl ray get workergroups -A
NAMESPACE                NAME            REPLICAS   CPUS      GPUS   TPUS   MEMORY         CLUSTER
default                  default-group   1/1        2         0      0      4Gi            dxia-test
explorer-one             gpuWorker       1/1        36        4      0      256Gi          yzhao
foundation-models        cpuWorker       1/1        20        0      0      200Gi          jacquelinew-v3
foundation-models        gpuWorker       1/1        200       8      0      1000Gi         jacquelinew-v3
foundation-models        redis           1/1        13        0      0      112Gi          jacquelinew-v3

$ kubectl ray get workergroups -n default
NAME            REPLICAS   CPUS   GPUS   TPUS   MEMORY   CLUSTER
default-group   1/1        2      0      0      4Gi      dxia-test

$ kubectl ray get workergroups -n foundation-models -c jacquelinew-v3
NAME        REPLICAS   CPUS   GPUS   TPUS   MEMORY   CLUSTER
cpuWorker   1/1        20     0      0      200Gi    jacquelinew-v3
gpuWorker   1/1        200    8      0      1000Gi   jacquelinew-v3
redis       1/1        13     0      0      112Gi    jacquelinew-v3

$ kubectl ray get workergroups gpuWorker -A
NAMESPACE           NAME        REPLICAS   CPUS   GPUS   TPUS   MEMORY   CLUSTER
explorer-one        gpuWorker   1/1        36     4      0      256Gi    yzhao
foundation-models   gpuWorker   1/1        200    8      0      1000Gi   jacquelinew-v3
```

[1]: ray-project#2926

Signed-off-by: David Xia <david@davidxia.com>

Author: davidxia

kubectl-plugin/pkg/cmd/create/create_workergroup.go

@@ -20,10 +20,6 @@ import (
 	"k8s.io/kubectl/pkg/util/templates"
 )
 
-const (
-	resourceNvidiaGPU = "nvidia.com/gpu"
-)
-
 type CreateWorkerGroupOptions struct {
 	configFlags       *genericclioptions.ConfigFlags
 	ioStreams         *genericclioptions.IOStreams
@@ -176,8 +172,8 @@ func createWorkerGroupSpec(options *CreateWorkerGroupOptions) rayv1.WorkerGroupS
 
 	gpuResource := resource.MustParse(options.workerGPU)
 	if !gpuResource.IsZero() {
-		podTemplate.Spec.Containers[0].Resources.Requests[corev1.ResourceName(resourceNvidiaGPU)] = gpuResource
-		podTemplate.Spec.Containers[0].Resources.Limits[corev1.ResourceName(resourceNvidiaGPU)] = gpuResource
+		podTemplate.Spec.Containers[0].Resources.Requests[corev1.ResourceName(util.ResourceNvidiaGPU)] = gpuResource
+		podTemplate.Spec.Containers[0].Resources.Limits[corev1.ResourceName(util.ResourceNvidiaGPU)] = gpuResource
 	}
 
 	return rayv1.WorkerGroupSpec{

kubectl-plugin/pkg/cmd/create/create_workergroup_test.go

@@ -8,6 +8,8 @@ import (
 	"k8s.io/apimachinery/pkg/api/resource"
 	"k8s.io/utils/ptr"
 
+	"github.com/ray-project/kuberay/kubectl-plugin/pkg/util"
+
 	rayv1 "github.com/ray-project/kuberay/ray-operator/apis/ray/v1"
 )
 
@@ -34,14 +36,14 @@ func TestCreateWorkerGroupSpec(t *testing.T) {
 						Image: "DEADBEEF",
 						Resources: corev1.ResourceRequirements{
 							Requests: corev1.ResourceList{
-								corev1.ResourceCPU:    resource.MustParse("2"),
-								corev1.ResourceMemory: resource.MustParse("5Gi"),
-								resourceNvidiaGPU:     resource.MustParse("1"),
+								corev1.ResourceCPU:     resource.MustParse("2"),
+								corev1.ResourceMemory:  resource.MustParse("5Gi"),
+								util.ResourceNvidiaGPU: resource.MustParse("1"),
 							},
 							Limits: corev1.ResourceList{
-								corev1.ResourceCPU:    resource.MustParse("2"),
-								corev1.ResourceMemory: resource.MustParse("5Gi"),
-								resourceNvidiaGPU:     resource.MustParse("1"),
+								corev1.ResourceCPU:     resource.MustParse("2"),
+								corev1.ResourceMemory:  resource.MustParse("5Gi"),
+								util.ResourceNvidiaGPU: resource.MustParse("1"),
 							},
 						},
 					},

kubectl-plugin/pkg/cmd/get/get.go

@@ -24,5 +24,6 @@ func NewGetCommand(streams genericclioptions.IOStreams) *cobra.Command {
 	}
 
 	cmd.AddCommand(NewGetClusterCommand(streams))
+	cmd.AddCommand(NewGetWorkerGroupCommand(streams))
 	return cmd
 }

kubectl-plugin/pkg/cmd/get/get_cluster.go

@@ -41,6 +41,7 @@ func NewGetClusterCommand(streams genericclioptions.IOStreams) *cobra.Command {
 
 	cmd := &cobra.Command{
 		Use:               "cluster [NAME]",
+		Aliases:           []string{"clusters"},
 		Short:             "Get cluster information.",
 		SilenceUsage:      true,
 		ValidArgsFunction: completion.RayClusterCompletionFunc(cmdFactory),