Create a new cloud-provider flag in order to catch wrong args directly and don't import the cloudprovider package and save ~50% in binary size

cmd/kubeadm/app/cmd/BUILD

@@ -24,13 +24,12 @@ go_library(
     deps = [
         "//cmd/kubeadm/app/apis/kubeadm:go_default_library",
         "//cmd/kubeadm/app/apis/kubeadm/v1alpha1:go_default_library",
+        "//cmd/kubeadm/app/cmd/flags:go_default_library",
         "//cmd/kubeadm/app/master:go_default_library",
         "//cmd/kubeadm/app/node:go_default_library",
         "//cmd/kubeadm/app/preflight:go_default_library",
         "//cmd/kubeadm/app/util:go_default_library",
         "//pkg/api:go_default_library",
-        "//pkg/cloudprovider:go_default_library",
-        "//pkg/cloudprovider/providers:go_default_library",
         "//pkg/kubectl/cmd/util:go_default_library",
         "//pkg/runtime:go_default_library",
         "//pkg/util/flag:go_default_library",

cmd/kubeadm/app/cmd/flags/BUILD

@@ -0,0 +1,18 @@
+package(default_visibility = ["//visibility:public"])
+
+licenses(["notice"])
+
+load(
+    "@io_bazel_rules_go//go:def.bzl",
+    "go_binary",
+    "go_library",
+    "go_test",
+    "cgo_library",
+)
+
+go_library(
+    name = "go_default_library",
+    srcs = ["cloudprovider.go"],
+    tags = ["automanaged"],
+    deps = ["//vendor:github.com/spf13/pflag"],
+)

cmd/kubeadm/app/cmd/flags/cloudprovider.go

@@ -0,0 +1,70 @@
+/*
+Copyright 2016 The Kubernetes 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 flags
+
+import (
+	"fmt"
+
+	"github.com/spf13/pflag"
+)
+
+var cloudproviders = []string{
+	"aws",
+	"azure",
+	"cloudstack",
+	"gce",
+	"mesos",
+	"openstack",
+	"ovirt",
+	"photon",
+	"rackspace",
+	"vsphere",
+}
+
+func NewCloudProviderFlag(provider *string) pflag.Value {
+	return &cloudProviderValue{provider: provider}
+}
+
+type cloudProviderValue struct {
+	provider *string
+}
+
+func (c *cloudProviderValue) String() string {
+	return *c.provider
+}
+
+func (c *cloudProviderValue) Set(s string) error {
+	if ValidateCloudProvider(s) {
+		*c.provider = s
+		return nil
+	}
+
+	return fmt.Errorf("cloud provider %q is not supported, you can use any of %v", s, cloudproviders)
+}
+
+func (c *cloudProviderValue) Type() string {
+	return "cloudprovider"
+}
+
+func ValidateCloudProvider(provider string) bool {
+	for _, supported := range cloudproviders {
+		if provider == supported {
+			return true
+		}
+	}
+	return false
+}

cmd/kubeadm/app/cmd/init.go

@@ -28,12 +28,11 @@ import (
 
 	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
 	kubeadmapiext "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1alpha1"
+	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/flags"
 	kubemaster "k8s.io/kubernetes/cmd/kubeadm/app/master"
 	"k8s.io/kubernetes/cmd/kubeadm/app/preflight"
 	kubeadmutil "k8s.io/kubernetes/cmd/kubeadm/app/util"
 	"k8s.io/kubernetes/pkg/api"
-	"k8s.io/kubernetes/pkg/cloudprovider"
-	_ "k8s.io/kubernetes/pkg/cloudprovider/providers"
 	"k8s.io/kubernetes/pkg/runtime"
 	netutil "k8s.io/kubernetes/pkg/util/net"
 )
@@ -103,9 +102,9 @@ func NewCmdInit(out io.Writer) *cobra.Command {
 		&cfg.Networking.DNSDomain, "service-dns-domain", cfg.Networking.DNSDomain,
 		`Use alternative domain for services, e.g. "myorg.internal"`,
 	)
-	cmd.PersistentFlags().StringVar(
-		&cfg.CloudProvider, "cloud-provider", cfg.CloudProvider,
-		`Enable cloud provider features (external load-balancers, storage, etc), e.g. "gce"`,
+	cmd.PersistentFlags().Var(
+		flags.NewCloudProviderFlag(&cfg.CloudProvider), "cloud-provider",
+		`Enable cloud provider features (external load-balancers, storage, etc). Note that you have to configure all kubelets manually`,
 	)
 
 	cmd.PersistentFlags().StringVar(
@@ -205,14 +204,12 @@ func NewInit(cfgPath string, cfg *kubeadmapi.MasterConfiguration, skipPreFlight
 	cfg.KubernetesVersion = ver
 	fmt.Println("Using Kubernetes version:", ver)
 
-	// TODO(phase1+) create a custom flag
+	// Warn about the limitations with the current cloudprovider solution.
 	if cfg.CloudProvider != "" {
-		if cloudprovider.IsCloudProvider(cfg.CloudProvider) {
-			fmt.Printf("cloud provider %q initialized for the control plane. Remember to set the same cloud provider flag on the kubelet.\n", cfg.CloudProvider)
-		} else {
-			return nil, fmt.Errorf("cloud provider %q is not supported, you can use any of %v, or leave it unset.\n", cfg.CloudProvider, cloudprovider.CloudProviders())
-		}
+		fmt.Println("WARNING: For cloudprovider integrations to work --cloud-provider must be set for all kubelets in the cluster.")
+		fmt.Println("\t(/etc/systemd/system/kubelet.service.d/10-kubeadm.conf should be edited for this purpose)")
 	}
+
 	return &Init{cfg: cfg}, nil
 }
 

cmd/kubeadm/app/master/manifests.go

@@ -34,10 +34,9 @@ import (
 )
 
 // Static pod definitions in golang form are included below so that `kubeadm init` can get going.
-
 const (
 	DefaultClusterName     = "kubernetes"
-	DefaultCloudConfigPath = "/etc/kubernetes/cloud-config.json"
+	DefaultCloudConfigPath = "/etc/kubernetes/cloud-config"
 
 	etcd                  = "etcd"
 	apiServer             = "apiserver"
@@ -264,6 +263,15 @@ func getAPIServerCommand(cfg *kubeadmapi.MasterConfiguration) (command []string)
 		command = append(command, etcdClientFileArg, etcdKeyFileArg)
 	}
 
+	if cfg.CloudProvider != "" {
+		command = append(command, "--cloud-provider="+cfg.CloudProvider)
+
+		// Only append the --cloud-config option if there's a such file
+		if _, err := os.Stat(DefaultCloudConfigPath); err == nil {
+			command = append(command, "--cloud-config="+DefaultCloudConfigPath)
+		}
+	}
+
 	return
 }