Add support for binaries to run as Windows services

This patch adds support for kubernetes to integrate
with Windows SCM.

As a first step both `kubelet` and `kube-proxy` can be registered as a service.

To create the service:
PS > sc.exe create <component_name> binPath= "<path_to_binary> --service <other_args>"
CMD > sc create <component_name> binPath= "<path_to_binary> --service <other_args>"

Please note that if the arguments contain spaces, it must be escaped.
Example:
PS > sc.exe create kubelet binPath= "C:\kubelet.exe --service --hostname-override 'minion' <other_args>"
CMD > sc create kubelet binPath= "C:\kubelet.exe --service --hostname-override 'minion' <other_args>"

Example to start the service:
PS > Start-Service kubelet; Start-Service kube-proxy
CMD > net start kubelet && net start kube-proxy

Example to stop the service:
PS > Stop-Service kubelet (-Force); Stop-Service kube-proxy (-Force)
CMD > net stop kubelet && net stop kube-proxy

Example to query the service:
PS > Get-Service kubelet; Get-Service kube-proxy;
CMD > sc.exe queryex kubelet && sc qc kubelet && sc.exe queryex kube-proxy && sc.exe qc kube-proxy

Signed-off-by: Alin Balutoiu <abalutoiu@cloudbasesolutions.com>
Signed-off-by: Alin Gabriel Serdean <aserdean@ovn.org>
Co-authored-by: Alin Gabriel Serdean <aserdean@ovn.org>

cmd/kube-proxy/app/BUILD

@@ -13,36 +13,47 @@ go_library(
         "server.go",
     ] + select({
         "@io_bazel_rules_go//go/platform:android": [
+            "init_others.go",
             "server_others.go",
         ],
         "@io_bazel_rules_go//go/platform:darwin": [
+            "init_others.go",
             "server_others.go",
         ],
         "@io_bazel_rules_go//go/platform:dragonfly": [
+            "init_others.go",
             "server_others.go",
         ],
         "@io_bazel_rules_go//go/platform:freebsd": [
+            "init_others.go",
             "server_others.go",
         ],
         "@io_bazel_rules_go//go/platform:linux": [
+            "init_others.go",
             "server_others.go",
         ],
         "@io_bazel_rules_go//go/platform:nacl": [
+            "init_others.go",
             "server_others.go",
         ],
         "@io_bazel_rules_go//go/platform:netbsd": [
+            "init_others.go",
             "server_others.go",
         ],
         "@io_bazel_rules_go//go/platform:openbsd": [
+            "init_others.go",
             "server_others.go",
         ],
         "@io_bazel_rules_go//go/platform:plan9": [
+            "init_others.go",
             "server_others.go",
         ],
         "@io_bazel_rules_go//go/platform:solaris": [
+            "init_others.go",
             "server_others.go",
         ],
         "@io_bazel_rules_go//go/platform:windows": [
+            "init_windows.go",
             "server_windows.go",
         ],
         "//conditions:default": [],
@@ -177,6 +188,7 @@ go_library(
             "//pkg/proxy/winkernel:go_default_library",
             "//pkg/proxy/winuserspace:go_default_library",
             "//pkg/util/netsh:go_default_library",
+            "//pkg/windows/service:go_default_library",
             "//vendor/k8s.io/apimachinery/pkg/types:go_default_library",
             "//vendor/k8s.io/apimachinery/pkg/util/net:go_default_library",
         ],

cmd/kube-proxy/app/init_others.go

@@ -0,0 +1,30 @@
+// +build !windows
+
+/*
+Copyright 2018 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 (
+	"github.com/spf13/pflag"
+)
+
+func initForOS(service bool) error {
+	return nil
+}
+
+func (o *Options) addOSFlags(fs *pflag.FlagSet) {
+}

cmd/kube-proxy/app/init_windows.go

@@ -0,0 +1,40 @@
+// +build windows
+
+/*
+Copyright 2018 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 (
+	"k8s.io/kubernetes/pkg/windows/service"
+
+	"github.com/spf13/pflag"
+)
+
+const (
+	serviceName = "kube-proxy"
+)
+
+func initForOS(windowsService bool) error {
+	if windowsService {
+		return service.InitService(serviceName)
+	}
+	return nil
+}
+
+func (o *Options) addOSFlags(fs *pflag.FlagSet) {
+	fs.BoolVar(&o.WindowsService, "windows-service", o.WindowsService, "Enable Windows Service Control Manager API integration")
+}

cmd/kube-proxy/app/server.go

@@ -100,6 +100,9 @@ type Options struct {
 	CleanupAndExit bool
 	// CleanupIPVS, when true, makes the proxy server clean up ipvs rules before running.
 	CleanupIPVS bool
+	// WindowsService should be set to true if kube-proxy is running as a service on Windows.
+	// Its corresponding flag only gets registered in Windows builds
+	WindowsService bool
 	// config is the proxy server's configuration object.
 	config *kubeproxyconfig.KubeProxyConfiguration
 
@@ -119,6 +122,7 @@ type Options struct {
 
 // AddFlags adds flags to fs and binds them to options.
 func (o *Options) AddFlags(fs *pflag.FlagSet) {
+	o.addOSFlags(fs)
 	fs.StringVar(&o.ConfigFile, "config", o.ConfigFile, "The path to the configuration file.")
 	fs.StringVar(&o.WriteConfigTo, "write-config-to", o.WriteConfigTo, "If set, write the default configuration values to this file and exit.")
 	fs.BoolVar(&o.CleanupAndExit, "cleanup-iptables", o.CleanupAndExit, "If true cleanup iptables and ipvs rules and exit.")
@@ -344,6 +348,10 @@ with the apiserver API to configure the proxy.`,
 			verflag.PrintAndExitIfRequested()
 			utilflag.PrintFlags(cmd.Flags())
 
+			if err := initForOS(opts.WindowsService); err != nil {
+				glog.Fatalf("failed OS init: %v", err)
+			}
+
 			cmdutil.CheckErr(opts.Complete())
 			cmdutil.CheckErr(opts.Validate(args))
 			cmdutil.CheckErr(opts.Run())