start: add --required-pods flag

Author: sttts

cmd/bootkube/start.go

@@ -2,6 +2,8 @@ package main
 
 import (
 	"errors"
+	"fmt"
+	"strings"
 
 	"github.com/spf13/cobra"
 
@@ -22,21 +24,31 @@ var (
 		assetDir        string
 		podManifestPath string
 		strict          bool
+		requiredPods    []string
 	}
 )
 
+var defaultRequiredPods = []string{
+	"kube-system/pod-checkpointer",
+	"kube-system/kube-apiserver",
+	"kube-system/kube-scheduler",
+	"kube-system/kube-controller-manager",
+}
+
 func init() {
 	cmdRoot.AddCommand(cmdStart)
 	cmdStart.Flags().StringVar(&startOpts.assetDir, "asset-dir", "", "Path to the cluster asset directory. Expected layout genereted by the `bootkube render` command.")
 	cmdStart.Flags().StringVar(&startOpts.podManifestPath, "pod-manifest-path", "/etc/kubernetes/manifests", "The location where the kubelet is configured to look for static pod manifests.")
 	cmdStart.Flags().BoolVar(&startOpts.strict, "strict", false, "Strict mode will cause bootkube to exit early if any manifests in the asset directory cannot be created.")
+	cmdStart.Flags().StringSliceVar(&startOpts.requiredPods, "required-pods", defaultRequiredPods, "List of pods with their namespace (written as <namespace>/<pod-name>) that are required to be running before the start command does the pivot.")
 }
 
 func runCmdStart(cmd *cobra.Command, args []string) error {
 	bk, err := bootkube.NewBootkube(bootkube.Config{
 		AssetDir:        startOpts.assetDir,
 		PodManifestPath: startOpts.podManifestPath,
 		Strict:          startOpts.strict,
+		RequiredPods:    startOpts.requiredPods,
 	})
 	if err != nil {
 		return err
@@ -57,5 +69,10 @@ func validateStartOpts(cmd *cobra.Command, args []string) error {
 	if startOpts.assetDir == "" {
 		return errors.New("missing required flag: --asset-dir")
 	}
+	for _, nsPod := range startOpts.requiredPods {
+		if len(strings.Split(nsPod, "/")) != 2 {
+			return fmt.Errorf("invalid required pod: expected %q to be of shape <namespace>/<pod-name>", nsPod)
+		}
+	}
 	return nil
 }

pkg/bootkube/bootkube.go

@@ -12,30 +12,26 @@ import (
 
 const assetTimeout = 20 * time.Minute
 
-var requiredPods = []string{
-	"pod-checkpointer",
-	"kube-apiserver",
-	"kube-scheduler",
-	"kube-controller-manager",
-}
-
 type Config struct {
 	AssetDir        string
 	PodManifestPath string
 	Strict          bool
+	RequiredPods    []string
 }
 
 type bootkube struct {
 	podManifestPath string
 	assetDir        string
 	strict          bool
+	requiredPods    []string
 }
 
 func NewBootkube(config Config) (*bootkube, error) {
 	return &bootkube{
 		assetDir:        config.AssetDir,
 		podManifestPath: config.PodManifestPath,
 		strict:          config.Strict,
+		requiredPods:    config.RequiredPods,
 	}, nil
 }
 
@@ -71,7 +67,7 @@ func (b *bootkube) Run() error {
 		return err
 	}
 
-	if err = WaitUntilPodsRunning(kubeConfig, requiredPods, assetTimeout); err != nil {
+	if err = WaitUntilPodsRunning(kubeConfig, b.requiredPods, assetTimeout); err != nil {
 		return err
 	}
 

pkg/bootkube/status.go

@@ -2,7 +2,6 @@ package bootkube
 
 import (
 	"fmt"
-	"path"
 	"reflect"
 	"strings"
 	"time"
@@ -65,10 +64,10 @@ func (s *statusController) Run() {
 	podStore, podController := cache.NewInformer(
 		&cache.ListWatch{
 			ListFunc: func(lo metav1.ListOptions) (runtime.Object, error) {
-				return s.client.Core().Pods("kube-system").List(options)
+				return s.client.Core().Pods("").List(options)
 			},
 			WatchFunc: func(lo metav1.ListOptions) (watch.Interface, error) {
-				return s.client.Core().Pods("kube-system").Watch(options)
+				return s.client.Core().Pods("").Watch(options)
 			},
 		},
 		&v1.Pod{},
@@ -110,24 +109,24 @@ func (s *statusController) PodStatus() (map[string]v1.PodPhase, error) {
 	status := make(map[string]v1.PodPhase)
 
 	podNames := s.podStore.ListKeys()
-	for _, pod := range s.watchPods {
+	for _, watchedPod := range s.watchPods {
 		// Pod names are suffixed with random data. Match on prefix
-		podName := pod
 		for _, pn := range podNames {
-			if strings.HasPrefix(pn, path.Join("kube-system", pod)) {
-				podName = pn
+			if strings.HasPrefix(pn, watchedPod) {
+				watchedPod = pn
+				break
 			}
 		}
-		p, exists, err := s.podStore.GetByKey(podName)
+		p, exists, err := s.podStore.GetByKey(watchedPod)
 		if err != nil {
 			return nil, err
 		}
 		if !exists {
-			status[pod] = doesNotExist
+			status[watchedPod] = doesNotExist
 			continue
 		}
 		if p, ok := p.(*v1.Pod); ok {
-			status[pod] = p.Status.Phase
+			status[watchedPod] = p.Status.Phase
 		}
 	}
 	return status, nil