Merge pull request #35592 from madhusudancs/federation-kubefed-04

Automatic merge from submit-queue

[Federation][(Un)join-01] Refactor common functions and structs into a util package.

Please review only the last commit here. This is based on PR #35495 which will be reviewed independently.

Design Doc: PR #34484

cc @kubernetes/sig-cluster-federation @quinton-hoole @nikhiljindal

federation/cmd/kubefed/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_binary(
+    name = "kubefed",
+    srcs = ["kubefed.go"],
+    tags = ["automanaged"],
+    deps = ["//federation/cmd/kubefed/app:go_default_library"],
+)

federation/cmd/kubefed/app/BUILD

@@ -0,0 +1,24 @@
+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 = ["kubefed.go"],
+    tags = ["automanaged"],
+    deps = [
+        "//federation/pkg/kubefed:go_default_library",
+        "//pkg/client/metrics/prometheus:go_default_library",
+        "//pkg/kubectl/cmd/util:go_default_library",
+        "//pkg/util/logs:go_default_library",
+        "//pkg/version/prometheus:go_default_library",
+    ],
+)

federation/cmd/kubefed/app/kubefed.go

@@ -0,0 +1,35 @@
+/*
+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 app
+
+import (
+	"os"
+
+	"k8s.io/kubernetes/federation/pkg/kubefed"
+	_ "k8s.io/kubernetes/pkg/client/metrics/prometheus" // for client metric registration
+	cmdutil "k8s.io/kubernetes/pkg/kubectl/cmd/util"
+	"k8s.io/kubernetes/pkg/util/logs"
+	_ "k8s.io/kubernetes/pkg/version/prometheus" // for version metric registration
+)
+
+func Run() error {
+	logs.InitLogs()
+	defer logs.FlushLogs()
+
+	cmd := kubefed.NewKubeFedCommand(cmdutil.NewFactory(nil), os.Stdin, os.Stdout, os.Stderr)
+	return cmd.Execute()
+}

federation/cmd/kubefed/kubefed.go

@@ -0,0 +1,30 @@
+/*
+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 main
+
+import (
+	"os"
+
+	"k8s.io/kubernetes/federation/cmd/kubefed/app"
+)
+
+func main() {
+	if err := app.Run(); err != nil {
+		os.Exit(1)
+	}
+	os.Exit(0)
+}

federation/pkg/kubefed/BUILD

@@ -14,11 +14,13 @@ go_library(
     name = "go_default_library",
     srcs = [
         "join.go",
+        "kubefed.go",
         "unjoin.go",
     ],
     tags = ["automanaged"],
     deps = [
         "//federation/apis/federation:go_default_library",
+        "//federation/pkg/kubefed/util:go_default_library",
         "//pkg/api:go_default_library",
         "//pkg/api/errors:go_default_library",
         "//pkg/api/unversioned:go_default_library",
@@ -30,6 +32,7 @@ go_library(
         "//pkg/kubectl/cmd/util:go_default_library",
         "//pkg/kubectl/resource:go_default_library",
         "//pkg/runtime:go_default_library",
+        "//pkg/util/flag:go_default_library",
         "//vendor:github.com/golang/glog",
         "//vendor:github.com/spf13/cobra",
     ],
@@ -46,6 +49,7 @@ go_test(
     deps = [
         "//federation/apis/federation:go_default_library",
         "//federation/apis/federation/v1beta1:go_default_library",
+        "//federation/pkg/kubefed/util:go_default_library",
         "//pkg/api:go_default_library",
         "//pkg/api/errors:go_default_library",
         "//pkg/api/testapi:go_default_library",

federation/pkg/kubefed/join.go

@@ -21,8 +21,7 @@ import (
 	"io"
 	"strings"
 
-	"k8s.io/kubernetes/pkg/api"
+	"k8s.io/kubernetes/federation/pkg/kubefed/util"
-	"k8s.io/kubernetes/pkg/client/unversioned/clientcmd"
 	clientcmdapi "k8s.io/kubernetes/pkg/client/unversioned/clientcmd/api"
 	"k8s.io/kubernetes/pkg/kubectl"
 	kubectlcmd "k8s.io/kubernetes/pkg/kubectl/cmd"
@@ -35,10 +34,6 @@ import (
 )
 
 const (
-	// KubeconfigSecretDataKey is the key name used in the secret to
-	// stores a cluster's credentials.
-	KubeconfigSecretDataKey = "kubeconfig"
-
 	// defaultClusterCIDR is the default CIDR range accepted by the
 	// joining API server. See `apis/federation.ClusterSpec` for
 	// details.
@@ -59,52 +54,9 @@ var (
 		kubectl join foo --host-cluster-context=bar`)
 )
 
-// JoinFederationConfig provides a filesystem based kubeconfig (via
-// `PathOptions()`) and a mechanism to talk to the federation host
-// cluster.
-type JoinFederationConfig interface {
-	// PathOptions provides filesystem based kubeconfig access.
-	PathOptions() *clientcmd.PathOptions
-	// HostFactory provides a mechanism to communicate with the
-	// cluster where federation control plane is hosted.
-	HostFactory(host, kubeconfigPath string) cmdutil.Factory
-}
-
-// joinFederationConfig implements JoinFederationConfig interface.
-type joinFederationConfig struct {
-	pathOptions *clientcmd.PathOptions
-}
-
-// Assert that `joinFederationConfig` implements the
-// `JoinFederationConfig` interface.
-var _ JoinFederationConfig = &joinFederationConfig{}
-
-func NewJoinFederationConfig(pathOptions *clientcmd.PathOptions) JoinFederationConfig {
-	return &joinFederationConfig{
-		pathOptions: pathOptions,
-	}
-}
-
-func (j *joinFederationConfig) PathOptions() *clientcmd.PathOptions {
-	return j.pathOptions
-}
-
-func (j *joinFederationConfig) HostFactory(host, kubeconfigPath string) cmdutil.Factory {
-	loadingRules := *j.pathOptions.LoadingRules
-	loadingRules.Precedence = j.pathOptions.GetLoadingPrecedence()
-	loadingRules.ExplicitPath = kubeconfigPath
-	overrides := &clientcmd.ConfigOverrides{
-		CurrentContext: host,
-	}
-
-	hostClientConfig := clientcmd.NewNonInteractiveDeferredLoadingClientConfig(&loadingRules, overrides)
-
-	return cmdutil.NewFactory(hostClientConfig)
-}
-
 // NewCmdJoin defines the `join` command that joins a cluster to a
 // federation.
-func NewCmdJoin(f cmdutil.Factory, cmdOut io.Writer, config JoinFederationConfig) *cobra.Command {
+func NewCmdJoin(f cmdutil.Factory, cmdOut io.Writer, config util.AdminConfig) *cobra.Command {
 	cmd := &cobra.Command{
 		Use:     "join CLUSTER_CONTEXT --host-cluster-context=HOST_CONTEXT",
 		Short:   "Join a cluster to a federation",
@@ -120,36 +72,35 @@ func NewCmdJoin(f cmdutil.Factory, cmdOut io.Writer, config JoinFederationConfig
 	cmdutil.AddValidateFlags(cmd)
 	cmdutil.AddPrinterFlags(cmd)
 	cmdutil.AddGeneratorFlags(cmd, cmdutil.ClusterV1Beta1GeneratorName)
-	addJoinFlags(cmd)
+	util.AddSubcommandFlags(cmd)
 	return cmd
 }
 
 // joinFederation is the implementation of the `join federation` command.
-func joinFederation(f cmdutil.Factory, cmdOut io.Writer, config JoinFederationConfig, cmd *cobra.Command, args []string) error {
+func joinFederation(f cmdutil.Factory, cmdOut io.Writer, config util.AdminConfig, cmd *cobra.Command, args []string) error {
-	name, err := kubectlcmd.NameFromCommandArgs(cmd, args)
+	joinFlags, err := util.GetSubcommandFlags(cmd, args)
 	if err != nil {
 		return err
 	}
-	host := cmdutil.GetFlagString(cmd, "host-cluster-context")
-	hostSystemNamespace := cmdutil.GetFlagString(cmd, "host-system-namespace")
-	kubeconfig := cmdutil.GetFlagString(cmd, "kubeconfig")
 	dryRun := cmdutil.GetDryRunFlag(cmd)
 
-	glog.V(2).Infof("Args and flags: name %s, host: %s, host-system-namespace: %s, kubeconfig: %s, dry-run: %s", name, host, hostSystemNamespace, kubeconfig, dryRun)
+	glog.V(2).Infof("Args and flags: name %s, host: %s, host-system-namespace: %s, kubeconfig: %s, dry-run: %s", joinFlags.Name, joinFlags.Host, joinFlags.HostSystemNamespace, joinFlags.Kubeconfig, dryRun)
 
 	po := config.PathOptions()
-	po.LoadingRules.ExplicitPath = kubeconfig
+	po.LoadingRules.ExplicitPath = joinFlags.Kubeconfig
 	clientConfig, err := po.GetStartingConfig()
 	if err != nil {
 		return err
 	}
-	generator, err := clusterGenerator(clientConfig, name)
+	generator, err := clusterGenerator(clientConfig, joinFlags.Name)
 	if err != nil {
 		glog.V(2).Infof("Failed creating cluster generator: %v", err)
 		return err
 	}
 	glog.V(2).Infof("Created cluster generator: %#v", generator)
 
+	hostFactory := config.HostFactory(joinFlags.Host, joinFlags.Kubeconfig)
+
 	// We are not using the `kubectl create secret` machinery through
 	// `RunCreateSubcommand` as we do to the cluster resource below
 	// because we have a bunch of requirements that the machinery does
@@ -165,8 +116,7 @@ func joinFederation(f cmdutil.Factory, cmdOut io.Writer, config JoinFederationCo
 	//    don't have to print the created secret in the default case.
 	// Having said that, secret generation machinery could be altered to
 	// suit our needs, but it is far less invasive and readable this way.
-	hostFactory := config.HostFactory(host, kubeconfig)
+	_, err = createSecret(hostFactory, clientConfig, joinFlags.HostSystemNamespace, joinFlags.Name, dryRun)
-	_, err = createSecret(hostFactory, clientConfig, hostSystemNamespace, name, dryRun)
 	if err != nil {
 		glog.V(2).Infof("Failed creating the cluster credentials secret: %v", err)
 		return err
@@ -174,19 +124,13 @@ func joinFederation(f cmdutil.Factory, cmdOut io.Writer, config JoinFederationCo
 	glog.V(2).Infof("Cluster credentials secret created")
 
 	return kubectlcmd.RunCreateSubcommand(f, cmd, cmdOut, &kubectlcmd.CreateSubcommandOptions{
-		Name:                name,
+		Name:                joinFlags.Name,
 		StructuredGenerator: generator,
 		DryRun:              dryRun,
 		OutputFormat:        cmdutil.GetFlagString(cmd, "output"),
 	})
 }
 
-func addJoinFlags(cmd *cobra.Command) {
-	cmd.Flags().String("kubeconfig", "", "Path to the kubeconfig file to use for CLI requests.")
-	cmd.Flags().String("host-cluster-context", "", "Host cluster context")
-	cmd.Flags().String("host-system-namespace", "federation-system", "Namespace in the host cluster where the federation system components are installed")
-}
-
 // minifyConfig is a wrapper around `clientcmdapi.MinifyConfig()` that
 // sets the current context to the given context before calling
 // `clientcmdapi.MinifyConfig()`.
@@ -223,34 +167,14 @@ func createSecret(hostFactory cmdutil.Factory, clientConfig *clientcmdapi.Config
 		return nil, err
 	}
 
-	configBytes, err := clientcmd.Write(*newClientConfig)
+	// Boilerplate to create the secret in the host cluster.
+	clientset, err := hostFactory.ClientSet()
 	if err != nil {
 		glog.V(2).Infof("Failed to serialize the kubeconfig for the given context %q: %v", name, err)
 		return nil, err
 	}
 
-	// Build the secret object with the minified and flattened
+	return util.CreateKubeconfigSecret(clientset, newClientConfig, namespace, name, dryRun)
-	// kubeconfig content.
-	secret := &api.Secret{
-		ObjectMeta: api.ObjectMeta{
-			Name:      name,
-			Namespace: namespace,
-		},
-		Data: map[string][]byte{
-			KubeconfigSecretDataKey: configBytes,
-		},
-	}
-
-	if !dryRun {
-		// Boilerplate to create the secret in the host cluster.
-		clientset, err := hostFactory.ClientSet()
-		if err != nil {
-			glog.V(2).Infof("Failed to retrieve the cluster clientset: %v", err)
-			return nil, err
-		}
-		return clientset.Core().Secrets(namespace).Create(secret)
-	}
-	return secret, nil
 }
 
 // clusterGenerator extracts the cluster information from the supplied

federation/pkg/kubefed/join_test.go

@@ -26,6 +26,7 @@ import (
 	"testing"
 
 	federationapi "k8s.io/kubernetes/federation/apis/federation/v1beta1"
+	"k8s.io/kubernetes/federation/pkg/kubefed/util"
 	"k8s.io/kubernetes/pkg/api"
 	"k8s.io/kubernetes/pkg/api/testapi"
 	"k8s.io/kubernetes/pkg/api/unversioned"
@@ -110,12 +111,12 @@ func TestJoinFederation(t *testing.T) {
 			t.Fatalf("[%d] unexpected error: %v", i, err)
 		}
 
-		joinConfig, err := newFakeJoinFederationConfig(hostFactory, tc.kubeconfigGlobal)
+		adminConfig, err := newFakeAdminConfig(hostFactory, tc.kubeconfigGlobal)
 		if err != nil {
 			t.Fatalf("[%d] unexpected error: %v", i, err)
 		}
 
-		cmd := NewCmdJoin(f, buf, joinConfig)
+		cmd := NewCmdJoin(f, buf, adminConfig)
 
 		cmd.Flags().Set("kubeconfig", tc.kubeconfigExplicit)
 		cmd.Flags().Set("host", "substrate")
@@ -171,28 +172,28 @@ func testJoinFederationFactory(name, server string) cmdutil.Factory {
 	return f
 }
 
-type fakeJoinFederationConfig struct {
+type fakeAdminConfig struct {
 	pathOptions *clientcmd.PathOptions
 	hostFactory cmdutil.Factory
 }
 
-func newFakeJoinFederationConfig(f cmdutil.Factory, kubeconfigGlobal string) (JoinFederationConfig, error) {
+func newFakeAdminConfig(f cmdutil.Factory, kubeconfigGlobal string) (util.AdminConfig, error) {
 	pathOptions := clientcmd.NewDefaultPathOptions()
 	pathOptions.GlobalFile = kubeconfigGlobal
 	pathOptions.EnvVar = ""
 
-	return &fakeJoinFederationConfig{
+	return &fakeAdminConfig{
 		pathOptions: pathOptions,
 		hostFactory: f,
 	}, nil
 }
 
-func (r *fakeJoinFederationConfig) PathOptions() *clientcmd.PathOptions {
+func (f *fakeAdminConfig) PathOptions() *clientcmd.PathOptions {
-	return r.pathOptions
+	return f.pathOptions
 }
 
-func (r *fakeJoinFederationConfig) HostFactory(host, kubeconfigPath string) cmdutil.Factory {
+func (f *fakeAdminConfig) HostFactory(host, kubeconfigPath string) cmdutil.Factory {
-	return r.hostFactory
+	return f.hostFactory
 }
 
 func fakeJoinHostFactory(name, server, token string) (cmdutil.Factory, error) {

federation/pkg/kubefed/kubefed.go

@@ -0,0 +1,75 @@
+/*
+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 kubefed
+
+import (
+	"io"
+
+	"k8s.io/kubernetes/federation/pkg/kubefed/util"
+	"k8s.io/kubernetes/pkg/client/unversioned/clientcmd"
+	kubectl "k8s.io/kubernetes/pkg/kubectl/cmd"
+	"k8s.io/kubernetes/pkg/kubectl/cmd/templates"
+	cmdutil "k8s.io/kubernetes/pkg/kubectl/cmd/util"
+	"k8s.io/kubernetes/pkg/util/flag"
+
+	"github.com/spf13/cobra"
+)
+
+// NewKubeFedCommand creates the `kubefed` command and its nested children.
+func NewKubeFedCommand(f cmdutil.Factory, in io.Reader, out, err io.Writer) *cobra.Command {
+	// Parent command to which all subcommands are added.
+	cmds := &cobra.Command{
+		Use:   "kubefed",
+		Short: "kubefed controls a Kubernetes Cluster Federation",
+		Long: templates.LongDesc(`
+      kubefed controls a Kubernetes Cluster Federation.
+
+      Find more information at https://github.com/kubernetes/kubernetes.`),
+		Run: runHelp,
+	}
+
+	f.BindFlags(cmds.PersistentFlags())
+	f.BindExternalFlags(cmds.PersistentFlags())
+
+	// From this point and forward we get warnings on flags that contain "_" separators
+	cmds.SetGlobalNormalizationFunc(flag.WarnWordSepNormalizeFunc)
+
+	groups := templates.CommandGroups{
+		{
+			Message: "Basic Commands:",
+			Commands: []*cobra.Command{
+				NewCmdJoin(f, out, util.NewAdminConfig(clientcmd.NewDefaultPathOptions())),
+				NewCmdUnjoin(f, out, err, util.NewAdminConfig(clientcmd.NewDefaultPathOptions())),
+			},
+		},
+	}
+	groups.Add(cmds)
+
+	filters := []string{
+		"options",
+	}
+	templates.ActsAsRootCommand(cmds, filters, groups...)
+
+	cmds.AddCommand(kubectl.NewCmdVersion(f, out))
+	cmds.AddCommand(kubectl.NewCmdOptions(out))
+
+	return cmds
+}
+
+func runHelp(cmd *cobra.Command, args []string) {
+	cmd.Help()
+}

federation/pkg/kubefed/unjoin.go

@@ -22,10 +22,10 @@ import (
 	"net/url"
 
 	federationapi "k8s.io/kubernetes/federation/apis/federation"
+	"k8s.io/kubernetes/federation/pkg/kubefed/util"
 	"k8s.io/kubernetes/pkg/api"
 	"k8s.io/kubernetes/pkg/api/errors"
 	"k8s.io/kubernetes/pkg/api/unversioned"
-	kubectlcmd "k8s.io/kubernetes/pkg/kubectl/cmd"
 	"k8s.io/kubernetes/pkg/kubectl/cmd/templates"
 	cmdutil "k8s.io/kubernetes/pkg/kubectl/cmd/util"
 	"k8s.io/kubernetes/pkg/kubectl/resource"
@@ -49,7 +49,7 @@ var (
 
 // NewCmdUnjoin defines the `unjoin` command that removes a cluster
 // from a federation.
-func NewCmdUnjoin(f cmdutil.Factory, cmdOut, cmdErr io.Writer, config JoinFederationConfig) *cobra.Command {
+func NewCmdUnjoin(f cmdutil.Factory, cmdOut, cmdErr io.Writer, config util.AdminConfig) *cobra.Command {
 	cmd := &cobra.Command{
 		Use:     "unjoin CLUSTER_NAME --host-cluster-context=HOST_CONTEXT",
 		Short:   "Unjoins a cluster from a federation",
@@ -61,42 +61,41 @@ func NewCmdUnjoin(f cmdutil.Factory, cmdOut, cmdErr io.Writer, config JoinFedera
 		},
 	}
 
-	addJoinFlags(cmd)
+	util.AddSubcommandFlags(cmd)
 	return cmd
 }
 
 // unjoinFederation is the implementation of the `unjoin` command.
-func unjoinFederation(f cmdutil.Factory, cmdOut, cmdErr io.Writer, config JoinFederationConfig, cmd *cobra.Command, args []string) error {
+func unjoinFederation(f cmdutil.Factory, cmdOut, cmdErr io.Writer, config util.AdminConfig, cmd *cobra.Command, args []string) error {
-	name, err := kubectlcmd.NameFromCommandArgs(cmd, args)
+	unjoinFlags, err := util.GetSubcommandFlags(cmd, args)
 	if err != nil {
 		return err
 	}
-	host := cmdutil.GetFlagString(cmd, "host-cluster-context")
-	hostSystemNamespace := cmdutil.GetFlagString(cmd, "host-system-namespace")
-	kubeconfig := cmdutil.GetFlagString(cmd, "kubeconfig")
 
-	cluster, err := popCluster(f, name)
+	cluster, err := popCluster(f, unjoinFlags.Name)
 	if err != nil {
 		return err
 	}
 	if cluster == nil {
-		fmt.Fprintf(cmdErr, "WARNING: cluster %q not found in federation, so its credentials' secret couldn't be deleted", name)
+		fmt.Fprintf(cmdErr, "WARNING: cluster %q not found in federation, so its credentials' secret couldn't be deleted", unjoinFlags.Name)
 		return nil
 	}
 
 	// We want a separate client factory to communicate with the
 	// federation host cluster. See join_federation.go for details.
-	hostFactory := config.HostFactory(host, kubeconfig)
+	hostFactory := config.HostFactory(unjoinFlags.Host, unjoinFlags.Kubeconfig)
-	err = deleteSecret(hostFactory, cluster.Spec.SecretRef.Name, hostSystemNamespace)
+	err = deleteSecret(hostFactory, cluster.Spec.SecretRef.Name, unjoinFlags.HostSystemNamespace)
 	if isNotFound(err) {
 		fmt.Fprintf(cmdErr, "WARNING: secret %q not found in the host cluster, so it couldn't be deleted", cluster.Spec.SecretRef.Name)
 	} else if err != nil {
 		return err
 	}
-	_, err = fmt.Fprintf(cmdOut, "Successfully removed cluster %q from federation\n", name)
+	_, err = fmt.Fprintf(cmdOut, "Successfully removed cluster %q from federation\n", unjoinFlags.Name)
 	return err
 }
 
+// popCluster fetches the cluster object with the given name, deletes
+// it and returns the deleted cluster object.
 func popCluster(f cmdutil.Factory, name string) (*federationapi.Cluster, error) {
 	// Boilerplate to create the secret in the host cluster.
 	mapper, typer := f.Object()
@@ -133,6 +132,8 @@ func popCluster(f cmdutil.Factory, name string) (*federationapi.Cluster, error)
 	return cluster, rh.Delete("", name)
 }
 
+// deleteSecret deletes the secret with the given name from the host
+// cluster.
 func deleteSecret(hostFactory cmdutil.Factory, name, namespace string) error {
 	clientset, err := hostFactory.ClientSet()
 	if err != nil {
@@ -141,6 +142,7 @@ func deleteSecret(hostFactory cmdutil.Factory, name, namespace string) error {
 	return clientset.Core().Secrets(namespace).Delete(name, &api.DeleteOptions{})
 }
 
+// isNotFound checks if the given error is a NotFound status error.
 func isNotFound(err error) bool {
 	statusErr := err
 	if urlErr, ok := err.(*url.Error); ok {

federation/pkg/kubefed/unjoin_test.go

@@ -125,12 +125,12 @@ func TestUnjoinFederation(t *testing.T) {
 		errBuf := bytes.NewBuffer([]byte{})
 
 		hostFactory := fakeUnjoinHostFactory(tc.cluster)
-		joinConfig, err := newFakeJoinFederationConfig(hostFactory, tc.kubeconfigGlobal)
+		adminConfig, err := newFakeAdminConfig(hostFactory, tc.kubeconfigGlobal)
 		if err != nil {
 			t.Fatalf("[%d] unexpected error: %v", i, err)
 		}
 
-		cmd := NewCmdUnjoin(f, buf, errBuf, joinConfig)
+		cmd := NewCmdUnjoin(f, buf, errBuf, adminConfig)
 
 		cmd.Flags().Set("kubeconfig", tc.kubeconfigExplicit)
 		cmd.Flags().Set("host", "substrate")

federation/pkg/kubefed/util/BUILD

@@ -0,0 +1,26 @@
+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 = ["util.go"],
+    tags = ["automanaged"],
+    deps = [
+        "//pkg/api:go_default_library",
+        "//pkg/client/clientset_generated/internalclientset:go_default_library",
+        "//pkg/client/unversioned/clientcmd:go_default_library",
+        "//pkg/client/unversioned/clientcmd/api:go_default_library",
+        "//pkg/kubectl/cmd:go_default_library",
+        "//pkg/kubectl/cmd/util:go_default_library",
+        "//vendor:github.com/spf13/cobra",
+    ],
+)

federation/pkg/kubefed/util/util.go

@@ -0,0 +1,130 @@
+/*
+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 util
+
+import (
+	"k8s.io/kubernetes/pkg/api"
+	client "k8s.io/kubernetes/pkg/client/clientset_generated/internalclientset"
+	"k8s.io/kubernetes/pkg/client/unversioned/clientcmd"
+	clientcmdapi "k8s.io/kubernetes/pkg/client/unversioned/clientcmd/api"
+	kubectlcmd "k8s.io/kubernetes/pkg/kubectl/cmd"
+	cmdutil "k8s.io/kubernetes/pkg/kubectl/cmd/util"
+
+	"github.com/spf13/cobra"
+)
+
+const (
+	// KubeconfigSecretDataKey is the key name used in the secret to
+	// stores a cluster's credentials.
+	KubeconfigSecretDataKey = "kubeconfig"
+)
+
+// AdminConfig provides a filesystem based kubeconfig (via
+// `PathOptions()`) and a mechanism to talk to the federation
+// host cluster.
+type AdminConfig interface {
+	// PathOptions provides filesystem based kubeconfig access.
+	PathOptions() *clientcmd.PathOptions
+	// HostFactory provides a mechanism to communicate with the
+	// cluster where federation control plane is hosted.
+	HostFactory(host, kubeconfigPath string) cmdutil.Factory
+}
+
+// adminConfig implements the AdminConfig interface.
+type adminConfig struct {
+	pathOptions *clientcmd.PathOptions
+}
+
+// NewAdminConfig creates an admin config for `kubefed` commands.
+func NewAdminConfig(pathOptions *clientcmd.PathOptions) AdminConfig {
+	return &adminConfig{
+		pathOptions: pathOptions,
+	}
+}
+
+func (a *adminConfig) PathOptions() *clientcmd.PathOptions {
+	return a.pathOptions
+}
+
+func (a *adminConfig) HostFactory(host, kubeconfigPath string) cmdutil.Factory {
+	loadingRules := *a.pathOptions.LoadingRules
+	loadingRules.Precedence = a.pathOptions.GetLoadingPrecedence()
+	loadingRules.ExplicitPath = kubeconfigPath
+	overrides := &clientcmd.ConfigOverrides{
+		CurrentContext: host,
+	}
+
+	hostClientConfig := clientcmd.NewNonInteractiveDeferredLoadingClientConfig(&loadingRules, overrides)
+
+	return cmdutil.NewFactory(hostClientConfig)
+}
+
+// SubcommandFlags holds the flags required by the subcommands of
+// `kubefed`.
+type SubcommandFlags struct {
+	Name                string
+	Host                string
+	HostSystemNamespace string
+	Kubeconfig          string
+}
+
+// AddSubcommandFlags adds the definition for `kubefed` subcommand
+// flags.
+func AddSubcommandFlags(cmd *cobra.Command) {
+	cmd.Flags().String("kubeconfig", "", "Path to the kubeconfig file to use for CLI requests.")
+	cmd.Flags().String("host", "", "Host cluster context")
+	cmd.Flags().String("host-system-namespace", "federation-system", "Namespace in the host cluster where the federation system components are installed")
+}
+
+// GetSubcommandFlags retrieves the command line flag values for the
+// `kubefed` subcommands.
+func GetSubcommandFlags(cmd *cobra.Command, args []string) (*SubcommandFlags, error) {
+	name, err := kubectlcmd.NameFromCommandArgs(cmd, args)
+	if err != nil {
+		return nil, err
+	}
+	return &SubcommandFlags{
+		Name:                name,
+		Host:                cmdutil.GetFlagString(cmd, "host"),
+		HostSystemNamespace: cmdutil.GetFlagString(cmd, "host-system-namespace"),
+		Kubeconfig:          cmdutil.GetFlagString(cmd, "kubeconfig"),
+	}, nil
+}
+
+func CreateKubeconfigSecret(clientset *client.Clientset, kubeconfig *clientcmdapi.Config, namespace, name string, dryRun bool) (*api.Secret, error) {
+	configBytes, err := clientcmd.Write(*kubeconfig)
+	if err != nil {
+		return nil, err
+	}
+
+	// Build the secret object with the minified and flattened
+	// kubeconfig content.
+	secret := &api.Secret{
+		ObjectMeta: api.ObjectMeta{
+			Name:      name,
+			Namespace: namespace,
+		},
+		Data: map[string][]byte{
+			KubeconfigSecretDataKey: configBytes,
+		},
+	}
+
+	if !dryRun {
+		return clientset.Core().Secrets(namespace).Create(secret)
+	}
+	return secret, nil
+}

hack/.linted_packages

@@ -52,6 +52,7 @@ federation/apis/federation/install
 federation/cmd/federation-apiserver
 federation/cmd/federation-controller-manager
 federation/cmd/genfeddocs
+federation/cmd/kubefed
 hack/boilerplate/test
 hack/cmd/teststale
 pkg/api

hack/lib/golang.sh

@@ -95,6 +95,7 @@ fi
 # The set of client targets that we are building for all platforms
 readonly KUBE_CLIENT_TARGETS=(
   cmd/kubectl
+  federation/cmd/kubefed
 )
 readonly KUBE_CLIENT_BINARIES=("${KUBE_CLIENT_TARGETS[@]##*/}")
 readonly KUBE_CLIENT_BINARIES_WIN=("${KUBE_CLIENT_BINARIES[@]/%/.exe}")