[Federation] Implement the kubefed command.

Also:
1. Add it to the client build targets list.
2. Register `kubefed join` and `kubefed unjoin` commands.

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

@@ -14,6 +14,7 @@ go_library(
     name = "go_default_library",
     srcs = [
         "join.go",
+        "kubefed.go",
         "unjoin.go",
     ],
     tags = ["automanaged"],
@@ -30,6 +31,7 @@ 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",
     ],

federation/pkg/kubefed/kubefed.go

@@ -0,0 +1,74 @@
+/*
+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/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, NewJoinFederationConfig(clientcmd.NewDefaultPathOptions())),
+				NewCmdUnjoin(f, out, err, NewJoinFederationConfig(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()
+}

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}")