Merge pull request #24511 from pbx0/kubelet-symlink

Automatic merge from submit-queue

cluster/images/hyperkube: create symlink for each server

Add a kubelet symlink so that the hyperkube image can appear as a kubelet image. https://github.com/kubernetes/kubernetes/issues/24510

cluster/images/hyperkube/Dockerfile

@@ -64,3 +64,6 @@ RUN chmod a+rx \
         /usr/share/google/safe_format_and_mount \
         /setup-files.sh \
         /make-ca-cert.sh
+
+# Create symlinks for each hyperkube server
+RUN /hyperkube --make-symlinks

cmd/hyperkube/hyperkube.go

@@ -41,10 +41,11 @@ type HyperKube struct {
 	Name string // The executable name, used for help and soft-link invocation
 	Long string // A long description of the binary.  It will be world wrapped before output.
 
-	servers     []Server
-	baseFlags   *pflag.FlagSet
-	out         io.Writer
-	helpFlagVal bool
+	servers             []Server
+	baseFlags           *pflag.FlagSet
+	out                 io.Writer
+	helpFlagVal         bool
+	makeSymlinksFlagVal bool
 }
 
 // AddServer adds a server to the HyperKube object.
@@ -75,6 +76,8 @@ func (hk *HyperKube) Flags() *pflag.FlagSet {
 		hk.baseFlags.SetOutput(ioutil.Discard)
 		hk.baseFlags.SetNormalizeFunc(utilflag.WordSepNormalizeFunc)
 		hk.baseFlags.BoolVarP(&hk.helpFlagVal, "help", "h", false, "help for "+hk.Name)
+		hk.baseFlags.BoolVar(&hk.makeSymlinksFlagVal, "make-symlinks", false, "create a symlink for each server in current directory")
+		hk.baseFlags.MarkHidden("make-symlinks") // hide this flag from appearing in servers' usage output
 
 		// These will add all of the "global" flags (defined with both the
 		// flag and pflag packages) to the new flag set we have.
@@ -117,7 +120,8 @@ func (hk *HyperKube) Printf(format string, i ...interface{}) {
 func (hk *HyperKube) Run(args []string) error {
 	// If we are called directly, parse all flags up to the first real
 	// argument.  That should be the server to run.
-	baseCommand := path.Base(args[0])
+	command := args[0]
+	baseCommand := path.Base(command)
 	serverName := baseCommand
 	if serverName == hk.Name {
 		args = args[1:]
@@ -133,6 +137,10 @@ func (hk *HyperKube) Run(args []string) error {
 			return err
 		}
 
+		if hk.makeSymlinksFlagVal {
+			return hk.MakeSymlinks(command)
+		}
+
 		verflag.PrintAndExitIfRequested()
 
 		args = baseFlags.Args()
@@ -200,7 +208,32 @@ Servers
 {{range .Servers}}
   {{.Name}}
 {{.Long | trim | wrap "    "}}{{end}}
+Call '{{.Name}} --make-symlinks' to create symlinks for each server in the local directory.
 Call '{{.Name}} <server> --help' for help on a specific server.
 `
 	util.ExecuteTemplate(hk.Out(), tt, hk)
 }
+
+// MakeSymlinks will create a symlink for each registered hyperkube server in the local directory.
+func (hk *HyperKube) MakeSymlinks(command string) error {
+	wd, err := os.Getwd()
+	if err != nil {
+		return err
+	}
+
+	var errs bool
+	for _, s := range hk.servers {
+		link := path.Join(wd, s.Name())
+
+		err := os.Symlink(command, link)
+		if err != nil {
+			errs = true
+			hk.Println(err)
+		}
+	}
+
+	if errs {
+		return errors.New("Error creating one or more symlinks.")
+	}
+	return nil
+}

hack/verify-flags/known-flags.txt

@@ -234,6 +234,7 @@ lock-file
 log-flush-frequency
 long-running-request-regexp
 low-diskspace-threshold-mb
+make-symlinks
 manifest-url
 manifest-url-header
 masquerade-all