Merge pull request #41710 from luxas/kubeadm_remove_cloudprovider_arg

Automatic merge from submit-queue (batch tested with PRs 41540, 41808, 41710, 41838, 41840)

kubeadm: Remove the --cloud-provider flag for beta init UX

**What this PR does / why we need it**:

We decided the `--cloud-provider` flag promises way too much compared to what it really does. There is a lot you have to do as an user in order to make the current cloud provider integrations to work. And since we're promising to support the `kubeadm init` UX on a beta level in v1.6, we can't have this flag in the UX. A lot is gonna change here... see proposal: https://github.com/kubernetes/community/pull/128

Once we find a cloudprovider solution we can support (probably using the new flow), we'll just add it.
For now, we'll just document how to do cloudprovider integrations by hand instead. 

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #

**Special notes for your reviewer**:

**Release note**:

```release-note
kubeadm: Remove the --cloud-provider flag for beta init UX
```
@jbeda @dmmcquay @mikedanese @roberthbailey @pires @errordeveloper

cmd/kubeadm/app/apis/kubeadm/validation/validation.go

@@ -25,10 +25,26 @@ import (
 	"k8s.io/kubernetes/pkg/registry/core/service/ipallocator"
 )
 
+// TODO: Break out the cloudprovider functionality out of core and only support the new flow
+// described in https://github.com/kubernetes/community/pull/128
+var cloudproviders = []string{
+	"aws",
+	"azure",
+	"cloudstack",
+	"gce",
+	"mesos",
+	"openstack",
+	"ovirt",
+	"photon",
+	"rackspace",
+	"vsphere",
+}
+
 func ValidateMasterConfiguration(c *kubeadm.MasterConfiguration) field.ErrorList {
 	allErrs := field.ErrorList{}
 	allErrs = append(allErrs, ValidateDiscovery(&c.Discovery, field.NewPath("discovery"))...)
 	allErrs = append(allErrs, ValidateDiscovery(&c.Discovery, field.NewPath("service subnet"))...)
+	allErrs = append(allErrs, ValidateCloudProvider(c.CloudProvider, field.NewPath("cloudprovider"))...)
 	return allErrs
 }
 
@@ -91,3 +107,15 @@ func ValidateServiceSubnet(subnet string, fldPath *field.Path) field.ErrorList {
 	}
 	return field.ErrorList{}
 }
+
+func ValidateCloudProvider(provider string, fldPath *field.Path) field.ErrorList {
+	if len(provider) == 0 {
+		return field.ErrorList{}
+	}
+	for _, supported := range cloudproviders {
+		if provider == supported {
+			return field.ErrorList{}
+		}
+	}
+	return field.ErrorList{field.Invalid(fldPath, nil, "cloudprovider not supported")}
+}

cmd/kubeadm/app/apis/kubeadm/validation/validation_test.go

@@ -71,6 +71,30 @@ func TestValidateServiceSubnet(t *testing.T) {
 	}
 }
 
+func TestValidateCloudProvider(t *testing.T) {
+	var tests = []struct {
+		s        string
+		f        *field.Path
+		expected bool
+	}{
+		{"", nil, true},      // if not provided, ok, it's optional
+		{"1234", nil, false}, // not supported
+		{"awws", nil, false}, // not supported
+		{"aws", nil, true},   // supported
+		{"gce", nil, true},   // supported
+	}
+	for _, rt := range tests {
+		actual := ValidateCloudProvider(rt.s, rt.f)
+		if (len(actual) == 0) != rt.expected {
+			t.Errorf(
+				"failed ValidateCloudProvider:\n\texpected: %t\n\t  actual: %t",
+				rt.expected,
+				(len(actual) == 0),
+			)
+		}
+	}
+}
+
 func TestValidateMasterConfiguration(t *testing.T) {
 	var tests = []struct {
 		s        *kubeadm.MasterConfiguration

cmd/kubeadm/app/cmd/BUILD

@@ -24,7 +24,6 @@ go_library(
         "//cmd/kubeadm/app/apis/kubeadm:go_default_library",
         "//cmd/kubeadm/app/apis/kubeadm/v1alpha1:go_default_library",
         "//cmd/kubeadm/app/apis/kubeadm/validation:go_default_library",
-        "//cmd/kubeadm/app/cmd/flags:go_default_library",
         "//cmd/kubeadm/app/constants:go_default_library",
         "//cmd/kubeadm/app/discovery:go_default_library",
         "//cmd/kubeadm/app/master:go_default_library",
@@ -79,9 +78,6 @@ filegroup(
 
 filegroup(
     name = "all-srcs",
-    srcs = [
+    srcs = [":package-srcs"],
-        ":package-srcs",
-        "//cmd/kubeadm/app/cmd/flags:all-srcs",
-    ],
     tags = ["automanaged"],
 )

cmd/kubeadm/app/cmd/flags/BUILD

@@ -1,28 +0,0 @@
-package(default_visibility = ["//visibility:public"])
-
-licenses(["notice"])
-
-load(
-    "@io_bazel_rules_go//go:def.bzl",
-    "go_library",
-)
-
-go_library(
-    name = "go_default_library",
-    srcs = ["cloudprovider.go"],
-    tags = ["automanaged"],
-    deps = ["//vendor:github.com/spf13/pflag"],
-)
-
-filegroup(
-    name = "package-srcs",
-    srcs = glob(["**"]),
-    tags = ["automanaged"],
-    visibility = ["//visibility:private"],
-)
-
-filegroup(
-    name = "all-srcs",
-    srcs = [":package-srcs"],
-    tags = ["automanaged"],
-)

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

@@ -1,70 +0,0 @@
-/*
-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

@@ -30,7 +30,6 @@ 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/apis/kubeadm/validation"
-	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/flags"
 	kubeadmconstants "k8s.io/kubernetes/cmd/kubeadm/app/constants"
 	"k8s.io/kubernetes/cmd/kubeadm/app/discovery"
 	kubemaster "k8s.io/kubernetes/cmd/kubeadm/app/master"
@@ -106,11 +105,6 @@ 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().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(
 		&cfg.KubernetesVersion, "use-kubernetes-version", cfg.KubernetesVersion,
 		`Choose a specific Kubernetes version for the control plane`,