From 7d53ad1fb0fcd49f71abc47d37cff597ab826d03 Mon Sep 17 00:00:00 2001
From: Clayton Coleman <ccoleman@redhat.com>
Date: Thu, 21 Mar 2019 14:14:49 -0400
Subject: [PATCH] Kubelet should request protobuf from the apiserver

The kubelet was not asking for application/vnd.kubernetes.protobuf
on list and get calls. It looks like we lost that code when we
moved to cert rotation. Clean up the client initialization path
and make sure that all non-dynamic clients use protobuf by default.
---
 cmd/kubelet/app/BUILD                         |  1 +
 cmd/kubelet/app/server.go                     | 25 +++++++++++++++++--
 .../k8s.io/apimachinery/pkg/runtime/types.go  |  5 ++--
 3 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/cmd/kubelet/app/BUILD b/cmd/kubelet/app/BUILD
index a837a646d6..5e9cf6fc81 100644
--- a/cmd/kubelet/app/BUILD
+++ b/cmd/kubelet/app/BUILD
@@ -113,6 +113,7 @@ go_library(
         "//staging/src/k8s.io/api/core/v1:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/api/resource:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/runtime:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/types:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/runtime:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/sets:go_default_library",
diff --git a/cmd/kubelet/app/server.go b/cmd/kubelet/app/server.go
index 69f0e35d0a..420c585fda 100644
--- a/cmd/kubelet/app/server.go
+++ b/cmd/kubelet/app/server.go
@@ -30,6 +30,7 @@ import (
 	"path"
 	"path/filepath"
 	"strconv"
+	"strings"
 	"time"
 
 	"github.com/coreos/go-systemd/daemon"
@@ -40,6 +41,7 @@ import (
 	v1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/resource"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/types"
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 	"k8s.io/apimachinery/pkg/util/sets"
@@ -757,6 +759,11 @@ func buildKubeletClientConfig(s *options.KubeletServer, nodeName types.NodeName)
 			return nil, nil, err
 		}
 
+		// use the correct content type for cert rotation, but don't set QPS
+		setContentTypeForClient(certConfig, s.ContentType)
+
+		kubeClientConfigOverrides(s, clientConfig)
+
 		clientCertificateManager, err := buildClientCertificateManager(certConfig, clientConfig, s.CertDirectory, nodeName)
 		if err != nil {
 			return nil, nil, err
@@ -764,7 +771,6 @@ func buildKubeletClientConfig(s *options.KubeletServer, nodeName types.NodeName)
 
 		// the rotating transport will use the cert from the cert manager instead of these files
 		transportConfig := restclient.AnonymousClientConfig(clientConfig)
-		kubeClientConfigOverrides(s, transportConfig)
 
 		// we set exitAfter to five minutes because we use this client configuration to request new certs - if we are unable
 		// to request new certs, we will be unable to continue normal operation. Exiting the process allows a wrapper
@@ -836,7 +842,7 @@ func buildClientCertificateManager(certConfig, clientConfig *restclient.Config,
 }
 
 func kubeClientConfigOverrides(s *options.KubeletServer, clientConfig *restclient.Config) {
-	clientConfig.ContentType = s.ContentType
+	setContentTypeForClient(clientConfig, s.ContentType)
 	// Override kubeconfig qps/burst settings from flags
 	clientConfig.QPS = float32(s.KubeAPIQPS)
 	clientConfig.Burst = int(s.KubeAPIBurst)
@@ -930,6 +936,21 @@ func InitializeTLS(kf *options.KubeletFlags, kc *kubeletconfiginternal.KubeletCo
 	return tlsOptions, nil
 }
 
+// setContentTypeForClient sets the appropritae content type into the rest config
+// and handles defaulting AcceptContentTypes based on that input.
+func setContentTypeForClient(cfg *restclient.Config, contentType string) {
+	if len(contentType) == 0 {
+		return
+	}
+	cfg.ContentType = contentType
+	switch contentType {
+	case runtime.ContentTypeProtobuf:
+		cfg.AcceptContentTypes = strings.Join([]string{runtime.ContentTypeProtobuf, runtime.ContentTypeJSON}, ",")
+	default:
+		// otherwise let the rest client perform defaulting
+	}
+}
+
 // RunKubelet is responsible for setting up and running a kubelet.  It is used in three different applications:
 //   1 Integration tests
 //   2 Kubelet binary
diff --git a/staging/src/k8s.io/apimachinery/pkg/runtime/types.go b/staging/src/k8s.io/apimachinery/pkg/runtime/types.go
index eb284eac27..3d3ebe5f9d 100644
--- a/staging/src/k8s.io/apimachinery/pkg/runtime/types.go
+++ b/staging/src/k8s.io/apimachinery/pkg/runtime/types.go
@@ -41,9 +41,8 @@ type TypeMeta struct {
 }
 
 const (
-	ContentTypeJSON string = "application/json"
-	ContentTypeYAML string = "application/yaml"
-
+	ContentTypeJSON     string = "application/json"
+	ContentTypeYAML     string = "application/yaml"
 	ContentTypeProtobuf string = "application/vnd.kubernetes.protobuf"
 )