WIP feat(helm): Add --node-selectors and --output flags to helm init

This feature enables users to specify more control over where Tiller pod
lands by allowing "node-selectors" to be specified. Alternatively, the
"--output" flag will skip install and dump Tiller's raw Deployment manifest
 to stdout so user may alter it as they see fit (probably with a JSON manipulation
  tool like jq).

Closes #2221

cmd/helm/init.go

@@ -26,6 +26,7 @@ import (
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/client-go/kubernetes"
 
+	"k8s.io/apimachinery/pkg/util/yaml"
 	"k8s.io/helm/cmd/helm/installer"
 	"k8s.io/helm/pkg/getter"
 	"k8s.io/helm/pkg/helm/helmpath"
@@ -120,6 +121,9 @@ func newInitCmd(out io.Writer) *cobra.Command {
 	f.BoolVar(&i.opts.EnableHostNetwork, "net-host", false, "install Tiller with net=host")
 	f.StringVar(&i.serviceAccount, "service-account", "", "name of service account")
 
+	f.StringVar(&i.opts.NodeSelectors, "node-selectors", "", "labels to select which node tiller lands on")
+	f.StringVarP(&i.opts.Output, "output", "o", "", "skip installation and output tiller's manifest in specified format")
+
 	return cmd
 }
 
@@ -159,31 +163,52 @@ func (i *initCmd) run() error {
 	i.opts.ImageSpec = i.image
 	i.opts.ServiceAccount = i.serviceAccount
 
-	if settings.Debug {
-		writeYAMLManifest := func(apiVersion, kind, body string, first, last bool) error {
-			w := i.out
-			if !first {
-				// YAML starting document boundary marker
-				if _, err := fmt.Fprintln(w, "---"); err != nil {
-					return err
-				}
-			}
-			if _, err := fmt.Fprintln(w, "apiVersion:", apiVersion); err != nil {
+	writeYAMLManifest := func(apiVersion, kind, body string, first, last bool) error {
+		w := i.out
+		if !first {
+			// YAML starting document boundary marker
+			if _, err := fmt.Fprintln(w, "---"); err != nil {
 				return err
 			}
-			if _, err := fmt.Fprintln(w, "kind:", kind); err != nil {
+		}
+		if _, err := fmt.Fprintln(w, "apiVersion:", apiVersion); err != nil {
+			return err
+		}
+		if _, err := fmt.Fprintln(w, "kind:", kind); err != nil {
+			return err
+		}
+		if _, err := fmt.Fprint(w, body); err != nil {
+			return err
+		}
+		if !last {
+			return nil
+		}
+		// YAML ending document boundary marker
+		_, err := fmt.Fprintln(w, "...")
+		return err
+	}
+	if len(i.opts.Output) > 0 {
+		switch i.opts.Output {
+		case "json":
+			var body string
+			var err error
+			if body, err = installer.DeploymentManifest(&i.opts); err != nil {
 				return err
 			}
-			if _, err := fmt.Fprint(w, body); err != nil {
+			jsonb, err := yaml.ToJSON([]byte(body))
+			if err != nil {
 				return err
 			}
-			if !last {
-				return nil
-			}
-			// YAML ending document boundary marker
-			_, err := fmt.Fprintln(w, "...")
-			return err
+			jsons := string(jsonb)
+			jsons = "{\"apiVersion\":\"extensions/v1beta1\",\"kind\":\"Deployment\"," + jsons[1:]
+			fmt.Fprint(i.out, jsons)
+
+			return nil
+		default:
+			return fmt.Errorf("Unknown output format: %s", i.opts.Output)
 		}
+	}
+	if settings.Debug {
 
 		var body string
 		var err error

cmd/helm/installer/install.go

@@ -19,6 +19,8 @@ package installer // import "k8s.io/helm/cmd/helm/installer"
 import (
 	"io/ioutil"
 
+	"strings"
+
 	"github.com/ghodss/yaml"
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -116,8 +118,26 @@ func generateLabels(labels map[string]string) map[string]string {
 	return labels
 }
 
+// parseNodeSelectors takes a comma delimited list of key=values pairs and returns a map
+func parseNodeSelectors(labels string) map[string]string {
+	kv := strings.Split(labels, ",")
+	nodeSelectors := map[string]string{}
+	for _, v := range kv {
+		el := strings.Split(v, "=")
+		if len(el) == 2 {
+			nodeSelectors[el[0]] = el[1]
+		}
+	}
+
+	return nodeSelectors
+}
+
 func generateDeployment(opts *Options) *v1beta1.Deployment {
 	labels := generateLabels(map[string]string{"name": "tiller"})
+	nodeSelectors := map[string]string{}
+	if len(opts.NodeSelectors) > 0 {
+		nodeSelectors = parseNodeSelectors(opts.NodeSelectors)
+	}
 	d := &v1beta1.Deployment{
 		ObjectMeta: metav1.ObjectMeta{
 			Namespace: opts.Namespace,
@@ -164,10 +184,8 @@ func generateDeployment(opts *Options) *v1beta1.Deployment {
 							},
 						},
 					},
-					HostNetwork: opts.EnableHostNetwork,
-					NodeSelector: map[string]string{
-						"beta.kubernetes.io/os": "linux",
-					},
+					HostNetwork:  opts.EnableHostNetwork,
+					NodeSelector: nodeSelectors,
 				},
 			},
 		},
@@ -203,6 +221,7 @@ func generateDeployment(opts *Options) *v1beta1.Deployment {
 			},
 		})
 	}
+
 	return d
 }
 

cmd/helm/installer/options.go

@@ -71,6 +71,12 @@ type Options struct {
 
 	// EnableHostNetwork installs Tiller with net=host.
 	EnableHostNetwork bool
+
+	// NodeSelectors determine which nodes Tiller can land on
+	NodeSelectors string
+
+	// Output dumps the Tiller manifest in the specified format (e.g. json) but skips Helm/Tiller installation
+	Output string
 }
 
 func (opts *Options) selectImage() string {