Kubernetes benchmarks: Refactor kubectl context to allow sets of clusters.

Also add sanity check to make sure each cluster works as part of
initialization, by running a sample pod within.

PiperOrigin-RevId: 710786751

test/kubernetes/benchmarks/BUILD

@@ -58,7 +58,7 @@ go_test(
     ],
     deps = [
         "//test/kubernetes/k8sctx",
-        "//test/kubernetes/k8sctx/autok8sctx",
+        "//test/kubernetes/k8sctx/kubectlctx",
         "//test/kubernetes/testcluster",
     ],
 )
@@ -89,7 +89,7 @@ go_test(
     ],
     deps = [
         "//test/kubernetes/k8sctx",
-        "//test/kubernetes/k8sctx/autok8sctx",
+        "//test/kubernetes/k8sctx/kubectlctx",
         "//test/kubernetes/testcluster",
     ],
 )
@@ -122,7 +122,7 @@ go_test(
     ],
     deps = [
         "//test/kubernetes/k8sctx",
-        "//test/kubernetes/k8sctx/autok8sctx",
+        "//test/kubernetes/k8sctx/kubectlctx",
         "//test/kubernetes/testcluster",
     ],
 )
@@ -155,7 +155,7 @@ go_test(
     ],
     deps = [
         "//test/kubernetes/k8sctx",
-        "//test/kubernetes/k8sctx/autok8sctx",
+        "//test/kubernetes/k8sctx/kubectlctx",
         "//test/kubernetes/testcluster",
     ],
 )
@@ -188,7 +188,7 @@ go_test(
     ],
     deps = [
         "//test/kubernetes/k8sctx",
-        "//test/kubernetes/k8sctx/autok8sctx",
+        "//test/kubernetes/k8sctx/kubectlctx",
         "//test/kubernetes/testcluster",
     ],
 )
@@ -222,7 +222,7 @@ go_test(
     ],
     deps = [
         "//test/kubernetes/k8sctx",
-        "//test/kubernetes/k8sctx/autok8sctx",
+        "//test/kubernetes/k8sctx/kubectlctx",
         "//test/kubernetes/testcluster",
     ],
 )
@@ -254,7 +254,7 @@ go_test(
     ],
     deps = [
         "//test/kubernetes/k8sctx",
-        "//test/kubernetes/k8sctx/autok8sctx",
+        "//test/kubernetes/k8sctx/kubectlctx",
         "//test/kubernetes/testcluster",
     ],
 )
@@ -287,7 +287,7 @@ go_test(
     ],
     deps = [
         "//test/kubernetes/k8sctx",
-        "//test/kubernetes/k8sctx/autok8sctx",
+        "//test/kubernetes/k8sctx/kubectlctx",
         "//test/kubernetes/testcluster",
     ],
 )
@@ -320,7 +320,7 @@ go_test(
     ],
     deps = [
         "//test/kubernetes/k8sctx",
-        "//test/kubernetes/k8sctx/autok8sctx",
+        "//test/kubernetes/k8sctx/kubectlctx",
         "//test/kubernetes/testcluster",
     ],
 )
@@ -352,7 +352,7 @@ go_test(
     ],
     deps = [
         "//test/kubernetes/k8sctx",
-        "//test/kubernetes/k8sctx/autok8sctx",
+        "//test/kubernetes/k8sctx/kubectlctx",
         "//test/kubernetes/testcluster",
     ],
 )
@@ -392,7 +392,7 @@ go_test(
     ],
     deps = [
         "//test/kubernetes/k8sctx",
-        "//test/kubernetes/k8sctx/autok8sctx",
+        "//test/kubernetes/k8sctx/kubectlctx",
         "//test/kubernetes/testcluster",
     ],
 )
@@ -426,7 +426,7 @@ go_test(
     ],
     deps = [
         "//test/kubernetes/k8sctx",
-        "//test/kubernetes/k8sctx/autok8sctx",
+        "//test/kubernetes/k8sctx/kubectlctx",
         "//test/kubernetes/testcluster",
     ],
 )
@@ -458,7 +458,7 @@ go_test(
     ],
     deps = [
         "//test/kubernetes/k8sctx",
-        "//test/kubernetes/k8sctx/autok8sctx",
+        "//test/kubernetes/k8sctx/kubectlctx",
         "//test/kubernetes/testcluster",
     ],
 )
@@ -491,7 +491,7 @@ go_test(
     ],
     deps = [
         "//test/kubernetes/k8sctx",
-        "//test/kubernetes/k8sctx/autok8sctx",
+        "//test/kubernetes/k8sctx/kubectlctx",
         "//test/kubernetes/testcluster",
     ],
 )

test/kubernetes/benchmarks/abslbuild_test.go

@@ -19,14 +19,14 @@ import (
 	"testing"
 
 	"gvisor.dev/gvisor/test/kubernetes/k8sctx"
-	"gvisor.dev/gvisor/test/kubernetes/k8sctx/autok8sctx"
+	"gvisor.dev/gvisor/test/kubernetes/k8sctx/kubectlctx"
 	"gvisor.dev/gvisor/test/kubernetes/testcluster"
 )
 
 // TestABSLBuild benchmarks building various Abseil C++ targets.
 func TestABSLBuild(t *testing.T) {
 	ctx := context.Background()
-	k8sCtx, err := autok8sctx.New(ctx)
+	k8sCtx, err := kubectlctx.New(ctx)
 	if err != nil {
 		t.Fatalf("Failed to get kubernetes context: %v", err)
 	}

test/kubernetes/benchmarks/ffmpeg_test.go

@@ -19,13 +19,13 @@ import (
 	"testing"
 
 	"gvisor.dev/gvisor/test/kubernetes/k8sctx"
-	"gvisor.dev/gvisor/test/kubernetes/k8sctx/autok8sctx"
+	"gvisor.dev/gvisor/test/kubernetes/k8sctx/kubectlctx"
 	"gvisor.dev/gvisor/test/kubernetes/testcluster"
 )
 
 func TestFfmpeg(t *testing.T) {
 	ctx := context.Background()
-	k8sCtx, err := autok8sctx.New(ctx)
+	k8sCtx, err := kubectlctx.New(ctx)
 	if err != nil {
 		t.Fatalf("Failed to get kubernetes context: %v", err)
 	}

test/kubernetes/benchmarks/grpc_test.go

@@ -19,13 +19,13 @@ import (
 	"testing"
 
 	"gvisor.dev/gvisor/test/kubernetes/k8sctx"
-	"gvisor.dev/gvisor/test/kubernetes/k8sctx/autok8sctx"
+	"gvisor.dev/gvisor/test/kubernetes/k8sctx/kubectlctx"
 	"gvisor.dev/gvisor/test/kubernetes/testcluster"
 )
 
 func TestGRPCBuild(t *testing.T) {
 	ctx := context.Background()
-	k8sCtx, err := autok8sctx.New(ctx)
+	k8sCtx, err := kubectlctx.New(ctx)
 	if err != nil {
 		t.Fatalf("Failed to get kubernetes context: %v", err)
 	}

test/kubernetes/benchmarks/gsutil_test.go

@@ -21,13 +21,13 @@ import (
 	"testing"
 
 	"gvisor.dev/gvisor/test/kubernetes/k8sctx"
-	"gvisor.dev/gvisor/test/kubernetes/k8sctx/autok8sctx"
+	"gvisor.dev/gvisor/test/kubernetes/k8sctx/kubectlctx"
 	"gvisor.dev/gvisor/test/kubernetes/testcluster"
 )
 
 func TestGSUtil(t *testing.T) {
 	ctx := context.Background()
-	k8sCtx, err := autok8sctx.New(ctx)
+	k8sCtx, err := kubectlctx.New(ctx)
 	if err != nil {
 		t.Fatalf("Failed to get kubernetes context: %v", err)
 	}

test/kubernetes/benchmarks/nginx_test.go

@@ -19,13 +19,13 @@ import (
 	"testing"
 
 	"gvisor.dev/gvisor/test/kubernetes/k8sctx"
-	"gvisor.dev/gvisor/test/kubernetes/k8sctx/autok8sctx"
+	"gvisor.dev/gvisor/test/kubernetes/k8sctx/kubectlctx"
 	"gvisor.dev/gvisor/test/kubernetes/testcluster"
 )
 
 func TestNginx(t *testing.T) {
 	ctx := context.Background()
-	k8sCtx, err := autok8sctx.New(ctx)
+	k8sCtx, err := kubectlctx.New(ctx)
 	if err != nil {
 		t.Fatalf("Failed to get kubernetes context: %v", err)
 	}

test/kubernetes/benchmarks/ollama_test.go

@@ -22,7 +22,7 @@ import (
 	"testing"
 
 	"gvisor.dev/gvisor/test/kubernetes/k8sctx"
-	"gvisor.dev/gvisor/test/kubernetes/k8sctx/autok8sctx"
+	"gvisor.dev/gvisor/test/kubernetes/k8sctx/kubectlctx"
 	"gvisor.dev/gvisor/test/kubernetes/testcluster"
 )
 
@@ -30,7 +30,7 @@ func TestOllama(t *testing.T) {
 	fmt.Fprint(os.Stderr, "HEADS UP: This test uses a huge container image which may take up to 30 minutes to download onto nodes the first time you run it.\n")
 
 	ctx := context.Background()
-	k8sCtx, err := autok8sctx.New(ctx)
+	k8sCtx, err := kubectlctx.New(ctx)
 	if err != nil {
 		t.Fatalf("Failed to get kubernetes context: %v", err)
 	}

test/kubernetes/benchmarks/postgresql_test.go

@@ -20,14 +20,14 @@ import (
 	"testing"
 
 	"gvisor.dev/gvisor/test/kubernetes/k8sctx"
-	"gvisor.dev/gvisor/test/kubernetes/k8sctx/autok8sctx"
+	"gvisor.dev/gvisor/test/kubernetes/k8sctx/kubectlctx"
 	"gvisor.dev/gvisor/test/kubernetes/testcluster"
 )
 
 // TestPostgresPGBench benchmarks a PostgreSQL database with pgbench.
 func TestPostgresPGBench(t *testing.T) {
 	ctx := context.Background()
-	k8sCtx, err := autok8sctx.New(ctx)
+	k8sCtx, err := kubectlctx.New(ctx)
 	if err != nil {
 		t.Fatalf("Failed to get kubernetes context: %v", err)
 	}

test/kubernetes/benchmarks/pytorch_test.go

@@ -19,7 +19,7 @@ import (
 	"testing"
 
 	"gvisor.dev/gvisor/test/kubernetes/k8sctx"
-	"gvisor.dev/gvisor/test/kubernetes/k8sctx/autok8sctx"
+	"gvisor.dev/gvisor/test/kubernetes/k8sctx/kubectlctx"
 	"gvisor.dev/gvisor/test/kubernetes/testcluster"
 )
 
@@ -49,7 +49,7 @@ func TestMobileNetV2(t *testing.T) {
 }
 
 func runTests(ctx context.Context, t *testing.T, tests []pytorchTest) {
-	k8sCtx, err := autok8sctx.New(ctx)
+	k8sCtx, err := kubectlctx.New(ctx)
 	if err != nil {
 		t.Fatalf("Failed to get kubernetes context: %v", err)
 	}

test/kubernetes/benchmarks/redis_test.go

@@ -19,14 +19,14 @@ import (
 	"testing"
 
 	"gvisor.dev/gvisor/test/kubernetes/k8sctx"
-	"gvisor.dev/gvisor/test/kubernetes/k8sctx/autok8sctx"
+	"gvisor.dev/gvisor/test/kubernetes/k8sctx/kubectlctx"
 	"gvisor.dev/gvisor/test/kubernetes/testcluster"
 )
 
 // TestRedis benchmarks redis servers on k8s clusters.
 func TestRedis(t *testing.T) {
 	ctx := context.Background()
-	k8sCtx, err := autok8sctx.New(ctx)
+	k8sCtx, err := kubectlctx.New(ctx)
 	if err != nil {
 		t.Fatalf("Failed to get kubernetes context: %v", err)
 	}

test/kubernetes/benchmarks/rubydev_test.go

@@ -19,14 +19,14 @@ import (
 	"testing"
 
 	"gvisor.dev/gvisor/test/kubernetes/k8sctx"
-	"gvisor.dev/gvisor/test/kubernetes/k8sctx/autok8sctx"
+	"gvisor.dev/gvisor/test/kubernetes/k8sctx/kubectlctx"
 	"gvisor.dev/gvisor/test/kubernetes/testcluster"
 )
 
 // TestRubyDev benchmarks a build job on k8s clusters.
 func TestRubyDev(t *testing.T) {
 	ctx := context.Background()
-	k8sCtx, err := autok8sctx.New(ctx)
+	k8sCtx, err := kubectlctx.New(ctx)
 	if err != nil {
 		t.Fatalf("Failed to get kubernetes context: %v", err)
 	}

test/kubernetes/benchmarks/stablediffusion_test.go

@@ -19,13 +19,13 @@ import (
 	"testing"
 
 	"gvisor.dev/gvisor/test/kubernetes/k8sctx"
-	"gvisor.dev/gvisor/test/kubernetes/k8sctx/autok8sctx"
+	"gvisor.dev/gvisor/test/kubernetes/k8sctx/kubectlctx"
 	"gvisor.dev/gvisor/test/kubernetes/testcluster"
 )
 
 func TestStableDiffusionXL(t *testing.T) {
 	ctx := context.Background()
-	k8sCtx, err := autok8sctx.New(ctx)
+	k8sCtx, err := kubectlctx.New(ctx)
 	if err != nil {
 		t.Fatalf("Failed to get kubernetes context: %v", err)
 	}

test/kubernetes/benchmarks/startup_test.go

@@ -19,13 +19,13 @@ import (
 	"testing"
 
 	"gvisor.dev/gvisor/test/kubernetes/k8sctx"
-	"gvisor.dev/gvisor/test/kubernetes/k8sctx/autok8sctx"
+	"gvisor.dev/gvisor/test/kubernetes/k8sctx/kubectlctx"
 	"gvisor.dev/gvisor/test/kubernetes/testcluster"
 )
 
 func TestStartup(t *testing.T) {
 	ctx := context.Background()
-	k8sCtx, err := autok8sctx.New(ctx)
+	k8sCtx, err := kubectlctx.New(ctx)
 	if err != nil {
 		t.Fatalf("Failed to get kubernetes context: %v", err)
 	}

test/kubernetes/benchmarks/tensorflow_test.go

@@ -19,13 +19,13 @@ import (
 	"testing"
 
 	"gvisor.dev/gvisor/test/kubernetes/k8sctx"
-	"gvisor.dev/gvisor/test/kubernetes/k8sctx/autok8sctx"
+	"gvisor.dev/gvisor/test/kubernetes/k8sctx/kubectlctx"
 	"gvisor.dev/gvisor/test/kubernetes/testcluster"
 )
 
 func TestTensorflowOnCPU(t *testing.T) {
 	ctx := context.Background()
-	k8sCtx, err := autok8sctx.New(ctx)
+	k8sCtx, err := kubectlctx.New(ctx)
 	if err != nil {
 		t.Fatalf("Failed to get kubernetes context: %v", err)
 	}

test/kubernetes/benchmarks/wordpress_test.go

@@ -19,13 +19,13 @@ import (
 	"testing"
 
 	"gvisor.dev/gvisor/test/kubernetes/k8sctx"
-	"gvisor.dev/gvisor/test/kubernetes/k8sctx/autok8sctx"
+	"gvisor.dev/gvisor/test/kubernetes/k8sctx/kubectlctx"
 	"gvisor.dev/gvisor/test/kubernetes/testcluster"
 )
 
 func TestWordpress(t *testing.T) {
 	ctx := context.Background()
-	k8sCtx, err := autok8sctx.New(ctx)
+	k8sCtx, err := kubectlctx.New(ctx)
 	if err != nil {
 		t.Fatalf("Failed to get kubernetes context: %v", err)
 	}

test/kubernetes/k8sctx/BUILD

@@ -7,7 +7,6 @@ package(
 
 go_library(
     name = "k8sctx",
-    testonly = True,
     srcs = [
         "k8sctx.go",
     ],

test/kubernetes/k8sctx/autok8sctx/kubectlctx.go

@@ -1,50 +0,0 @@
-// Copyright 2024 The gVisor Authors.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-//go:build !false
-// +build !false
-
-// Package autok8sctx provides a KubernetesContext that uses a kubectl config
-// and context to determine the test cluster to use for tests and benchmarks.
-// See parent package (`k8sctx`) for more info.
-package autok8sctx
-
-import (
-	"context"
-	"errors"
-	"fmt"
-
-	"gvisor.dev/gvisor/runsc/flag"
-	"gvisor.dev/gvisor/test/kubernetes/k8sctx"
-	"gvisor.dev/gvisor/test/kubernetes/testcluster"
-	"gvisor.dev/gvisor/tools/gvisor_k8s_tool/provider/kubectl"
-)
-
-var (
-	kubectlContextName = flag.String("kubectl-context-name", "", "Name of the kubectl context to use within the kubectl config")
-)
-
-// New creates a KubernetesContext using flags to determine which kubectl
-// config and kubectl context to use as the test cluster.
-func New(ctx context.Context) (k8sctx.KubernetesContext, error) {
-	if *kubectlContextName == "" {
-		return nil, errors.New("no kubectl context name specified")
-	}
-	cluster, err := kubectl.NewCluster(*kubectlContextName)
-	if err != nil {
-		return nil, fmt.Errorf("cannot initialize cluster %q: %w", *kubectlContextName, err)
-	}
-	testCluster := testcluster.NewTestClusterFromClient(*kubectlContextName, cluster.Client())
-	return k8sctx.NewSingleCluster(testCluster), nil
-}

test/kubernetes/k8sctx/k8sctx.go

@@ -21,7 +21,6 @@ package k8sctx
 
 import (
 	"context"
-	"sync"
 	"testing"
 
 	"gvisor.dev/gvisor/test/kubernetes/testcluster"
@@ -66,34 +65,33 @@ func ForEachCluster(ctx context.Context, t *testing.T, k8sCtx KubernetesContext,
 	}
 }
 
-// singleCluster implements KubernetesContext using a single cluster.
-type singleCluster struct {
-	mu      sync.Mutex
-	cluster *testcluster.TestCluster
+// clusters implements KubernetesContext using a set of clusters.
+type clusters struct {
+	clustersCh chan *testcluster.TestCluster
 }
 
 // Cluster implements KubernetesContext.Cluster.
-func (sc *singleCluster) Cluster(ctx context.Context, t *testing.T) (*testcluster.TestCluster, func()) {
-	sc.mu.Lock()
-	defer sc.mu.Unlock()
-	cl := sc.cluster
-	sc.cluster = nil
-	return cl, func() {
-		if cl != nil {
-			sc.mu.Lock()
-			defer sc.mu.Unlock()
-			sc.cluster = cl
+func (cs *clusters) Cluster(ctx context.Context, t *testing.T) (*testcluster.TestCluster, func()) {
+	select {
+	case cluster := <-cs.clustersCh:
+		return cluster, func() {
+			cs.clustersCh <- cluster
 		}
+	default:
+		return nil, func() {}
 	}
 }
 
 // ResolveImage implements KubernetesContext.ResolveImage.
-func (*singleCluster) ResolveImage(ctx context.Context, imageName string) (string, error) {
+func (*clusters) ResolveImage(ctx context.Context, imageName string) (string, error) {
 	return imageName, nil
 }
 
-// NewSingleCluster creates a KubernetesContext that uses a single, static
-// test cluster.
-func NewSingleCluster(cluster *testcluster.TestCluster) KubernetesContext {
-	return &singleCluster{cluster: cluster}
+// New creates a KubernetesContext that set of test clusters.
+func New(testClusters ...*testcluster.TestCluster) KubernetesContext {
+	clustersCh := make(chan *testcluster.TestCluster, len(testClusters))
+	for _, cluster := range testClusters {
+		clustersCh <- cluster
+	}
+	return &clusters{clustersCh: clustersCh}
 }

test/kubernetes/k8sctx/kubectlctx/BUILD

@@ -6,8 +6,7 @@ package(
 )
 
 go_library(
-    name = "autok8sctx",
-    testonly = True,
+    name = "kubectlctx",
     srcs = ["kubectlctx.go"],
     nogo = False,
     visibility = [
@@ -15,8 +14,13 @@ go_library(
     ],
     deps = [
         "//runsc/flag",
+        "//test/kubernetes:test_range_config_go_proto",
         "//test/kubernetes/k8sctx",
         "//test/kubernetes/testcluster",
         "//tools/gvisor_k8s_tool/provider/kubectl",
+        "@io_k8s_client_go//kubernetes:go_default_library",
+        "@io_k8s_client_go//tools/clientcmd:go_default_library",
+        "@org_golang_google_protobuf//encoding/prototext:go_default_library",
+        "@org_golang_x_sync//errgroup:go_default_library",
     ],
 )

test/kubernetes/k8sctx/kubectlctx/kubectlctx.go

@@ -0,0 +1,142 @@
+// Copyright 2024 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package kubectlctx provides a KubernetesContext that uses one or more
+// kubectl configs to determine the cluster(s) to use for tests and benchmarks.
+// See parent package (`k8sctx`) for more info.
+package kubectlctx
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"golang.org/x/sync/errgroup"
+	"google.golang.org/protobuf/encoding/prototext"
+	"gvisor.dev/gvisor/runsc/flag"
+	"gvisor.dev/gvisor/test/kubernetes/k8sctx"
+	testpb "gvisor.dev/gvisor/test/kubernetes/test_range_config_go_proto"
+	"gvisor.dev/gvisor/test/kubernetes/testcluster"
+	"gvisor.dev/gvisor/tools/gvisor_k8s_tool/provider/kubectl"
+	"k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/tools/clientcmd"
+)
+
+var (
+	rangeDir            = flag.String("range-dir", "", "A directory containing a test_range.textproto text file describing multiple clusters to use for tests and benchmarks; takes precedence over --kubectl-context-name")
+	kubectlContext      = flag.String("kubectl-context", "", "The name of the kubectl context to use; if unset, use the default context within the kubectl config at KUBECONFIG")
+	testNodepoolRuntime = flag.String("test-nodepool-runtime", "", "if set, override the runtime used for pods scheduled on the 'test' nodepool. If unset, the nodepool default is used")
+)
+
+// New creates a KubernetesContext using flags to determine which clusters
+// to use for tests and benchmarks.
+func New(ctx context.Context) (k8sctx.KubernetesContext, error) {
+	if *rangeDir != "" && *kubectlContext != "" {
+		return nil, fmt.Errorf("cannot use --range-dir and --kubectl-context at the same time")
+	}
+	var clusters []*testcluster.TestCluster
+	var err error
+	if *rangeDir != "" {
+		clusters, err = NewFromRangeDir(ctx, *rangeDir)
+	} else {
+		clusters, err = NewFromKubectlContext(ctx, *kubectlContext)
+	}
+	if err != nil {
+		return nil, fmt.Errorf("cannot initialize test clusters: %w", err)
+	}
+	if *testNodepoolRuntime != "" {
+		overriddenRuntime := testcluster.RuntimeType(*testNodepoolRuntime)
+		if !overriddenRuntime.IsValid() {
+			return nil, fmt.Errorf("invalid runtime type %q", *testNodepoolRuntime)
+		}
+		for _, cluster := range clusters {
+			cluster.OverrideTestNodepoolRuntime(overriddenRuntime)
+		}
+	}
+	if err := verifyClusters(ctx, clusters); err != nil {
+		return nil, fmt.Errorf("cannot verify clusters are working: %w", err)
+	}
+	return k8sctx.New(clusters...), nil
+}
+
+// NewFromRangeDir creates a set of test clusters from a test range directory.
+func NewFromRangeDir(ctx context.Context, rangeDir string) ([]*testcluster.TestCluster, error) {
+	rangeFile := filepath.Join(rangeDir, "test_range.textproto")
+	rangeFileData, err := os.ReadFile(rangeFile)
+	if err != nil {
+		return nil, fmt.Errorf("cannot read range file %q: %w", rangeFile, err)
+	}
+	var testRange testpb.TestRange
+	if err := prototext.Unmarshal(rangeFileData, &testRange); err != nil {
+		return nil, fmt.Errorf("error unmarshalling range file %q: %v", rangeFile, err)
+	}
+	if len(testRange.GetClusters()) == 0 {
+		return nil, fmt.Errorf("range file %q has no clusters", rangeFile)
+	}
+	clusters := make([]*testcluster.TestCluster, len(testRange.GetClusters()))
+	for i, cluster := range testRange.GetClusters() {
+		configPath := cluster.GetKubectlConfig()
+		if configPath == "" {
+			return nil, fmt.Errorf("cluster %q has no kubectl config path", cluster.GetCluster())
+		}
+		cfg, err := clientcmd.LoadFromFile(configPath)
+		if err != nil {
+			return nil, fmt.Errorf("cannot load kubectl config at %q for cluster %q: %w", configPath, cluster.GetCluster(), err)
+		}
+		contextName := cluster.GetKubectlContext()
+		if contextName == "" {
+			contextName = cfg.CurrentContext
+		}
+		restConfig, err := clientcmd.NewNonInteractiveClientConfig(*cfg, contextName, nil, clientcmd.NewDefaultClientConfigLoadingRules()).ClientConfig()
+		if err != nil {
+			return nil, fmt.Errorf("cannot load REST client config for cluster %q: %w", cluster.GetCluster(), err)
+		}
+		kubeClient, err := kubernetes.NewForConfig(restConfig)
+		if err != nil {
+			return nil, fmt.Errorf("cannot create Kubernetes client for cluster %q: %w", cluster.GetCluster(), err)
+		}
+		clusters[i] = testcluster.NewTestClusterFromClient(cluster.GetCluster(), kubeClient)
+	}
+	return clusters, nil
+}
+
+// NewFromKubectlContext creates a test cluster from a kubectl config.
+//
+// If the kubectl config is not specified, the default kubectl config is used.
+// If the kubectl context is not specified, the default context within the
+// kubectl config is used.
+func NewFromKubectlContext(ctx context.Context, kubectlContext string) ([]*testcluster.TestCluster, error) {
+	cluster, err := kubectl.NewCluster(kubectlContext)
+	if err != nil {
+		return nil, fmt.Errorf("cannot initialize cluster from kubectl config: %w", err)
+	}
+	clusterName := "test-cluster" // Default name.
+	if kubectlContext != "" {
+		clusterName = kubectlContext
+	}
+	return []*testcluster.TestCluster{testcluster.NewTestClusterFromClient(clusterName, cluster.Client())}, nil
+}
+
+// verifyClusters verifies that all clusters are working.
+func verifyClusters(ctx context.Context, clusters []*testcluster.TestCluster) error {
+	var g errgroup.Group
+	for _, cluster := range clusters {
+		c := cluster
+		g.Go(func() error {
+			return c.SanityCheck(ctx)
+		})
+	}
+	return g.Wait()
+}