Merge pull request #65368 from deads2k/server-17-discovery

Automatic merge from submit-queue (batch tested with PRs 61330, 64793, 64675, 65059, 65368). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

legacy api endpoints only support v1 ever

The legacy API endpoint should only ever have a v1.  This removes flexibility we don't need or want.

@kubernetes/sig-api-machinery-pr-reviews 
@sttts 

```release-note
NONE
```

staging/src/k8s.io/apiserver/pkg/endpoints/discovery/legacy.go

@@ -32,23 +32,21 @@ import (
 // legacyRootAPIHandler creates a webservice serving api group discovery.
 type legacyRootAPIHandler struct {
 	// addresses is used to build cluster IPs for discovery.
-	addresses   Addresses
-	apiPrefix   string
-	serializer  runtime.NegotiatedSerializer
-	apiVersions []string
+	addresses  Addresses
+	apiPrefix  string
+	serializer runtime.NegotiatedSerializer
 }
 
-func NewLegacyRootAPIHandler(addresses Addresses, serializer runtime.NegotiatedSerializer, apiPrefix string, apiVersions []string) *legacyRootAPIHandler {
+func NewLegacyRootAPIHandler(addresses Addresses, serializer runtime.NegotiatedSerializer, apiPrefix string) *legacyRootAPIHandler {
 	// Because in release 1.1, /apis returns response with empty APIVersion, we
 	// use stripVersionNegotiatedSerializer to keep the response backwards
 	// compatible.
 	serializer = stripVersionNegotiatedSerializer{serializer}
 
 	return &legacyRootAPIHandler{
-		addresses:   addresses,
-		apiPrefix:   apiPrefix,
-		serializer:  serializer,
-		apiVersions: apiVersions,
+		addresses:  addresses,
+		apiPrefix:  apiPrefix,
+		serializer: serializer,
 	}
 }
 
@@ -71,7 +69,7 @@ func (s *legacyRootAPIHandler) handle(req *restful.Request, resp *restful.Respon
 	clientIP := utilnet.GetClientIP(req.Request)
 	apiVersions := &metav1.APIVersions{
 		ServerAddressByClientCIDRs: s.addresses.ServerAddressByClientCIDRs(clientIP),
-		Versions:                   s.apiVersions,
+		Versions:                   []string{"v1"},
 	}
 
 	responsewriters.WriteObjectNegotiated(s.serializer, schema.GroupVersion{}, resp.ResponseWriter, req.Request, http.StatusOK, apiVersions)

staging/src/k8s.io/apiserver/pkg/server/genericapiserver.go

@@ -341,14 +341,9 @@ func (s *GenericAPIServer) InstallLegacyAPIGroup(apiPrefix string, apiGroupInfo
 		return err
 	}
 
-	// setup discovery
-	apiVersions := []string{}
-	for _, groupVersion := range apiGroupInfo.PrioritizedVersions {
-		apiVersions = append(apiVersions, groupVersion.Version)
-	}
 	// Install the version handler.
 	// Add a handler at /<apiPrefix> to enumerate the supported api versions.
-	s.Handler.GoRestfulContainer.Add(discovery.NewLegacyRootAPIHandler(s.discoveryAddresses, s.Serializer, apiPrefix, apiVersions).WebService())
+	s.Handler.GoRestfulContainer.Add(discovery.NewLegacyRootAPIHandler(s.discoveryAddresses, s.Serializer, apiPrefix).WebService())
 
 	return nil
 }