Coerce componentconfig/v1alpha1 KubeSchedulerConfiguration to kubescheduler.config.k8s.io/v1alpha1

cmd/kube-scheduler/app/options/BUILD

@@ -20,9 +20,12 @@ go_library(
         "//pkg/scheduler/apis/config/validation:go_default_library",
         "//pkg/scheduler/factory:go_default_library",
         "//staging/src/k8s.io/api/core/v1:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/api/meta:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/apis/config:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1/unstructured:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/runtime:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/runtime/schema:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/runtime/serializer/json:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/uuid:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/validation/field:go_default_library",

cmd/kube-scheduler/app/options/configfile.go

@@ -17,11 +17,16 @@ limitations under the License.
 package options
 
 import (
+	"bytes"
 	"errors"
+	"fmt"
 	"io/ioutil"
 	"os"
 
+	"k8s.io/apimachinery/pkg/api/meta"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/apimachinery/pkg/runtime/serializer/json"
 	kubeschedulerconfig "k8s.io/kubernetes/pkg/scheduler/apis/config"
 	kubeschedulerscheme "k8s.io/kubernetes/pkg/scheduler/apis/config/scheme"
@@ -40,8 +45,48 @@ func loadConfigFromFile(file string) (*kubeschedulerconfig.KubeSchedulerConfigur
 func loadConfig(data []byte) (*kubeschedulerconfig.KubeSchedulerConfiguration, error) {
 	configObj := &kubeschedulerconfig.KubeSchedulerConfiguration{}
 	if err := runtime.DecodeInto(kubeschedulerscheme.Codecs.UniversalDecoder(), data, configObj); err != nil {
+
+		// if this is a componentconfig/v1alpha1 KubeSchedulerConfiguration object, coerce it to kubescheduler.config.k8s.io/v1alpha1 with a warning
+		// TODO: drop this block in 1.13
+		if runtime.IsNotRegisteredError(err) {
+			originalErr := err
+			var (
+				u               = &unstructured.Unstructured{}
+				codec           = json.NewYAMLSerializer(json.DefaultMetaFactory, kubeschedulerscheme.Scheme, kubeschedulerscheme.Scheme)
+				legacyConfigGVK = schema.GroupVersionKind{Group: "componentconfig", Version: "v1alpha1", Kind: "KubeSchedulerConfiguration"}
+			)
+			// attempt to decode to an unstructured object
+			obj, gvk, err := codec.Decode(data, nil, u)
+
+			// if this errored, or the object we read was not the legacy alpha gvk, return the original error
+			if err != nil || gvk == nil || *gvk != legacyConfigGVK {
+				return nil, originalErr
+			}
+
+			fmt.Printf("WARNING: the provided config file is an unsupported apiVersion (%q), which will be removed in future releases\n\n", legacyConfigGVK.GroupVersion().String())
+			fmt.Printf("WARNING: switch to command-line flags or update your config file apiVersion to %q\n\n", kubeschedulerconfigv1alpha1.SchemeGroupVersion.String())
+			fmt.Printf("WARNING: apiVersions at alpha-level are not guaranteed to be supported in future releases\n\n")
+
+			// attempt to coerce to the new alpha gvk
+			if err := meta.NewAccessor().SetAPIVersion(obj, kubeschedulerconfigv1alpha1.SchemeGroupVersion.String()); err != nil {
+				// return the original error on failure
+				return nil, originalErr
+			}
+
+			// attempt to encode the coerced apiVersion back to bytes
+			buffer := bytes.NewBuffer([]byte{})
+			if err := codec.Encode(obj, buffer); err != nil {
+				// return the original error on failure
+				return nil, originalErr
+			}
+
+			// re-attempt to load the coerced apiVersion
+			return loadConfig(buffer.Bytes())
+		}
+
 		return nil, err
 	}
+
 	return configObj, nil
 }
 

cmd/kube-scheduler/app/options/options_test.go

@@ -111,6 +111,17 @@ leaderElection:
 		t.Fatal(err)
 	}
 
+	invalidconfigFile := filepath.Join(tmpDir, "scheduler_invalid.yaml")
+	if err := ioutil.WriteFile(invalidconfigFile, []byte(fmt.Sprintf(`
+apiVersion: componentconfig/v1alpha2
+kind: KubeSchedulerConfiguration
+clientConnection:
+  kubeconfig: "%s"
+leaderElection:
+  leaderElect: true`, configKubeconfig)), os.FileMode(0600)); err != nil {
+		t.Fatal(err)
+	}
+
 	// flag-specified kubeconfig
 	flagKubeconfig := filepath.Join(tmpDir, "flag.kubeconfig")
 	if err := ioutil.WriteFile(flagKubeconfig, []byte(fmt.Sprintf(`
@@ -195,9 +206,53 @@ users:
 			},
 		},
 		{
-			name:          "config file in componentconfig/v1alpha1",
-			options:       &Options{ConfigFile: oldconfigFile},
-			expectedError: "no kind \"KubeSchedulerConfiguration\" is registered for version \"componentconfig/v1alpha1\" in scheme",
+			name: "config file in componentconfig/v1alpha1",
+			options: &Options{
+				ConfigFile: oldconfigFile,
+				ComponentConfig: func() kubeschedulerconfig.KubeSchedulerConfiguration {
+					cfg, err := newDefaultComponentConfig()
+					if err != nil {
+						t.Fatal(err)
+					}
+					return *cfg
+				}(),
+			},
+			// TODO: switch this to expect an error in 1.13 when the special-case coercion is removed from loadConfig
+			// expectedError: "no kind \"KubeSchedulerConfiguration\" is registered for version \"componentconfig/v1alpha1\"",
+			expectedUsername: "config",
+			expectedConfig: kubeschedulerconfig.KubeSchedulerConfiguration{
+				SchedulerName:                  "default-scheduler",
+				AlgorithmSource:                kubeschedulerconfig.SchedulerAlgorithmSource{Provider: &defaultSource},
+				HardPodAffinitySymmetricWeight: 1,
+				HealthzBindAddress:             "0.0.0.0:10251",
+				MetricsBindAddress:             "0.0.0.0:10251",
+				FailureDomains:                 "kubernetes.io/hostname,failure-domain.beta.kubernetes.io/zone,failure-domain.beta.kubernetes.io/region",
+				LeaderElection: kubeschedulerconfig.KubeSchedulerLeaderElectionConfiguration{
+					LeaderElectionConfiguration: apiserverconfig.LeaderElectionConfiguration{
+						LeaderElect:   true,
+						LeaseDuration: metav1.Duration{Duration: 15 * time.Second},
+						RenewDeadline: metav1.Duration{Duration: 10 * time.Second},
+						RetryPeriod:   metav1.Duration{Duration: 2 * time.Second},
+						ResourceLock:  "endpoints",
+					},
+					LockObjectNamespace: "kube-system",
+					LockObjectName:      "kube-scheduler",
+				},
+				ClientConnection: apimachineryconfig.ClientConnectionConfiguration{
+					Kubeconfig:  configKubeconfig,
+					QPS:         50,
+					Burst:       100,
+					ContentType: "application/vnd.kubernetes.protobuf",
+				},
+				PercentageOfNodesToScore: 50,
+				BindTimeoutSeconds:       &defaultBindTimeoutSeconds,
+			},
+		},
+
+		{
+			name:          "invalid config file in componentconfig/v1alpha2",
+			options:       &Options{ConfigFile: invalidconfigFile},
+			expectedError: "no kind \"KubeSchedulerConfiguration\" is registered for version \"componentconfig/v1alpha2\"",
 		},
 		{
 			name: "kubeconfig flag",