add dynamic rest mapper to the admission plugin initializer

pkg/cmd/server/origin/master.go

@@ -13,6 +13,7 @@ import (
 	"gopkg.in/natefinch/lumberjack.v2"
 
 	apiextensionsinformers "k8s.io/apiextensions-apiserver/pkg/client/informers/internalversion"
+	"k8s.io/apimachinery/pkg/util/wait"
 	auditinternal "k8s.io/apiserver/pkg/apis/audit"
 	auditpolicy "k8s.io/apiserver/pkg/audit/policy"
 	apifilters "k8s.io/apiserver/pkg/endpoints/filters"
@@ -257,6 +258,16 @@ func (c *MasterConfig) Run(kubeAPIServerConfig *kubeapiserver.Config, controller
 	// add post-start hooks
 	aggregatedAPIServer.GenericAPIServer.AddPostStartHookOrDie("template.openshift.io-sharednamespace", c.ensureOpenShiftSharedResourcesNamespace)
 	aggregatedAPIServer.GenericAPIServer.AddPostStartHookOrDie("authorization.openshift.io-bootstrapclusterroles", bootstrappolicy.Policy().EnsureRBACPolicy())
+	aggregatedAPIServer.GenericAPIServer.AddPostStartHookOrDie("admission.openshift.io-RefreshRESTMapper", func(context apiserver.PostStartHookContext) error {
+		c.RESTMapper.Reset()
+		go func() {
+			wait.PollUntil(10*time.Second, func() (bool, error) {
+				c.RESTMapper.Reset()
+				return false, nil
+			}, context.StopCh)
+		}()
+		return nil
+	})
 	for name, fn := range extraPostStartHooks {
 		aggregatedAPIServer.GenericAPIServer.AddPostStartHookOrDie(name, fn)
 	}

pkg/cmd/server/origin/master_config.go

@@ -11,6 +11,7 @@ import (
 	"github.com/golang/glog"
 
 	kapierrors "k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/apimachinery/pkg/api/meta"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/labels"
 	"k8s.io/apimachinery/pkg/runtime/schema"
@@ -32,6 +33,8 @@ import (
 	"k8s.io/apiserver/pkg/authorization/authorizerfactory"
 	authorizerunion "k8s.io/apiserver/pkg/authorization/union"
 	apirequest "k8s.io/apiserver/pkg/endpoints/request"
+	"k8s.io/client-go/discovery"
+	cacheddiscovery "k8s.io/client-go/discovery/cached"
 	kubeclientgoinformers "k8s.io/client-go/informers"
 	kubeclientgoclient "k8s.io/client-go/kubernetes"
 	restclient "k8s.io/client-go/rest"
@@ -92,6 +95,8 @@ import (
 type MasterConfig struct {
 	Options configapi.MasterConfig
 
+	RESTMapper *discovery.DeferredDiscoveryRESTMapper
+
 	// RESTOptionsGetter provides access to storage and RESTOptions for a particular resource
 	RESTOptionsGetter restoptions.Getter
 
@@ -222,6 +227,10 @@ func BuildMasterConfig(options configapi.MasterConfig, informers InformerAccess)
 		options.ProjectConfig.ProjectRequestMessage,
 	)
 
+	// Use a discovery client capable of being refreshed.
+	discoveryClient := cacheddiscovery.NewMemCacheClient(privilegedLoopbackKubeClientsetInternal.Discovery())
+	restMapper := discovery.NewDeferredDiscoveryRESTMapper(discoveryClient, meta.InterfacesForUnstructured)
+
 	// punch through layers to build this in order to get a string for a cloud provider file
 	// TODO refactor us into a forward building flow with a side channel like this
 	kubeOptions, err := kubernetes.BuildKubeAPIserverOptions(options)
@@ -248,8 +257,7 @@ func BuildMasterConfig(options configapi.MasterConfig, informers InformerAccess)
 		informers.GetInternalKubeInformers(),
 		authorizer,
 		cloudConfig,
-		// TODO: use a dynamic restmapper. See https://github.com/kubernetes/kubernetes/pull/42615.
-		kapi.Registry.RESTMapper(),
+		restMapper,
 		quotaRegistry)
 	openshiftPluginInitializer := &oadmission.PluginInitializer{
 		OpenshiftClient:              privilegedLoopbackOpenShiftClient,
@@ -295,6 +303,8 @@ func BuildMasterConfig(options configapi.MasterConfig, informers InformerAccess)
 	config := &MasterConfig{
 		Options: options,
 
+		RESTMapper: restMapper,
+
 		RESTOptionsGetter: restOptsGetter,
 
 		RuleResolver:   ruleResolver,