Merge pull request #527 from Sarsate/rootdir-flag

Adds a flag to specify root working directory.

cmd/kubelet/kubelet.go

@@ -26,6 +26,7 @@ import (
 	"net/http"
 	"os"
 	"os/exec"
+	"path"
 	"strings"
 	"time"
 
@@ -40,6 +41,8 @@ import (
 	"github.com/google/cadvisor/client"
 )
 
+const defaultRootDir = "/var/lib/kubelet"
+
 var (
 	config             = flag.String("config", "", "Path to the config file or directory of files")
 	syncFrequency      = flag.Duration("sync_frequency", 10*time.Second, "Max period between synchronizing running containers and config")
@@ -51,6 +54,7 @@ var (
 	hostnameOverride   = flag.String("hostname_override", "", "If non-empty, will use this string as identification instead of the actual hostname.")
 	dockerEndpoint     = flag.String("docker_endpoint", "", "If non-empty, use this for the docker endpoint to communicate with")
 	etcdServerList     util.StringList
+	rootDirectory      = flag.String("root_dir", defaultRootDir, "Directory path for managing kubelet files (volume mounts,etc).")
 )
 
 func init() {
@@ -105,6 +109,12 @@ func main() {
 
 	hostname := getHostname()
 
+	if *rootDirectory == "" {
+		glog.Fatal("Invalid root directory path.")
+	}
+	*rootDirectory = path.Clean(*rootDirectory)
+	os.MkdirAll(*rootDirectory, 0750)
+
 	// source of all configuration
 	cfg := kconfig.NewPodConfig(kconfig.PodConfigNotificationSnapshotAndUpdates)
 
@@ -133,7 +143,8 @@ func main() {
 		getHostname(),
 		dockerClient,
 		cadvisorClient,
-		etcdClient)
+		etcdClient,
+		*rootDirectory)
 
 	// start the kubelet
 	go util.Forever(func() { k.Run(cfg.Updates()) }, 0)

pkg/kubelet/kubelet.go

@@ -62,12 +62,14 @@ func NewMainKubelet(
 	hn string,
 	dc DockerInterface,
 	cc CadvisorInterface,
-	ec tools.EtcdClient) *Kubelet {
+	ec tools.EtcdClient,
+	rd string) *Kubelet {
 	return &Kubelet{
 		hostname:       hn,
 		dockerClient:   dc,
 		cadvisorClient: cc,
 		etcdClient:     ec,
+		rootDirectory:  rd,
 	}
 }
 
@@ -83,8 +85,9 @@ func NewIntegrationTestKubelet(hn string, dc DockerInterface) *Kubelet {
 
 // Kubelet is the main kubelet implementation.
 type Kubelet struct {
-	hostname     string
-	dockerClient DockerInterface
+	hostname      string
+	dockerClient  DockerInterface
+	rootDirectory string
 
 	// Optional, no events will be sent without it
 	etcdClient tools.EtcdClient
@@ -210,7 +213,7 @@ func milliCPUToShares(milliCPU int) int {
 func (kl *Kubelet) mountExternalVolumes(manifest *api.ContainerManifest) (volumeMap, error) {
 	podVolumes := make(volumeMap)
 	for _, vol := range manifest.Volumes {
-		extVolume, err := volume.CreateVolume(&vol, manifest.ID)
+		extVolume, err := volume.CreateVolume(&vol, manifest.ID, kl.rootDirectory)
 		if err != nil {
 			return nil, err
 		}

pkg/kubelet/kubelet_test.go

@@ -61,6 +61,7 @@ func makeTestKubelet(t *testing.T) (*Kubelet, *tools.FakeEtcdClient, *FakeDocker
 	kubelet.dockerClient = fakeDocker
 	kubelet.dockerPuller = &FakeDockerPuller{}
 	kubelet.etcdClient = fakeEtcdClient
+	kubelet.rootDirectory = "/tmp/kubelet"
 	return kubelet, fakeEtcdClient, fakeDocker
 }
 
@@ -445,6 +446,11 @@ func TestMakeVolumesAndBinds(t *testing.T) {
 				Name:      "disk4",
 				ReadOnly:  false,
 			},
+			{
+				MountPath: "/mnt/path5",
+				Name:      "disk5",
+				ReadOnly:  false,
+			},
 		},
 	}
 
@@ -455,12 +461,13 @@ func TestMakeVolumesAndBinds(t *testing.T) {
 
 	podVolumes := make(volumeMap)
 	podVolumes["disk4"] = &volume.HostDirectory{"/mnt/host"}
+	podVolumes["disk5"] = &volume.EmptyDirectory{"disk5", "podID", "/var/lib/kubelet"}
 
 	volumes, binds := makeVolumesAndBinds(&pod, &container, podVolumes)
 
 	expectedVolumes := []string{"/mnt/path", "/mnt/path2"}
 	expectedBinds := []string{"/exports/pod.test/disk:/mnt/path", "/exports/pod.test/disk2:/mnt/path2:ro", "/mnt/path3:/mnt/path3",
-		"/mnt/host:/mnt/path4"}
+		"/mnt/host:/mnt/path4", "/var/lib/kubelet/podID/volumes/empty/disk5:/mnt/path5"}
 
 	if len(volumes) != len(expectedVolumes) {
 		t.Errorf("Unexpected volumes. Expected %#v got %#v.  Container was: %#v", expectedVolumes, volumes, container)

pkg/volume/volume.go

@@ -18,17 +18,18 @@ package volume
 
 import (
 	"errors"
-	"fmt"
 	"os"
+	"path"
+
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 	"github.com/golang/glog"
 )
 
-
 // All volume types are expected to implement this interface
 type Interface interface {
 	// Prepares and mounts/unpacks the volume to a directory path.
 	// This procedure must be idempotent.
+	// TODO(jonesdl) SetUp should return an error if it fails.
 	SetUp()
 	// Returns the directory path the volume is mounted to.
 	GetPath() string
@@ -56,16 +57,18 @@ func (hostVol *HostDirectory) GetPath() string {
 // EmptyDirectory volumes are temporary directories exposed to the pod.
 // These do not persist beyond the lifetime of a pod.
 type EmptyDirectory struct {
-	Name string
-	PodID string
+	Name    string
+	PodID   string
+	RootDir string
 }
 
 // SetUp creates the new directory.
 func (emptyDir *EmptyDirectory) SetUp() {
-	if _, err := os.Stat(emptyDir.GetPath()); os.IsNotExist(err) {
-		os.MkdirAll(emptyDir.GetPath(), 0750)
+	path := emptyDir.GetPath()
+	if _, err := os.Stat(path); os.IsNotExist(err) {
+		os.MkdirAll(path, 0750)
 	} else {
-		glog.Warningf("Directory already exists: (%v)", emptyDir.GetPath())
+		glog.Warningf("Directory already exists: (%v)", path)
 	}
 }
 
@@ -74,9 +77,7 @@ func (emptyDir *EmptyDirectory) SetUp() {
 func (emptyDir *EmptyDirectory) TearDown() {}
 
 func (emptyDir *EmptyDirectory) GetPath() string {
-	// TODO(jonesdl) We will want to add a flag to designate a root
-	// directory for kubelet to write to. For now this will just be /exports
-	return fmt.Sprintf("/exports/%v/%v", emptyDir.PodID, emptyDir.Name)
+	return path.Join(emptyDir.RootDir, emptyDir.PodID, "volumes", "empty", emptyDir.Name)
 }
 
 // Interprets API volume as a HostDirectory
@@ -85,13 +86,13 @@ func createHostDirectory(volume *api.Volume) *HostDirectory {
 }
 
 // Interprets API volume as an EmptyDirectory
-func createEmptyDirectory(volume *api.Volume, podID string) *EmptyDirectory {
-	return &EmptyDirectory{volume.Name, podID}
+func createEmptyDirectory(volume *api.Volume, podID string, rootDir string) *EmptyDirectory {
+	return &EmptyDirectory{volume.Name, podID, rootDir}
 }
 
 // CreateVolume returns an Interface capable of mounting a volume described by an
 // *api.Volume and whether or not it is mounted, or an error.
-func CreateVolume(volume *api.Volume, podID string) (Interface, error) {
+func CreateVolume(volume *api.Volume, podID string, rootDir string) (Interface, error) {
 	source := volume.Source
 	// TODO(jonesdl) We will want to throw an error here when we no longer
 	// support the default behavior.
@@ -104,7 +105,7 @@ func CreateVolume(volume *api.Volume, podID string) (Interface, error) {
 	if source.HostDirectory != nil {
 		vol = createHostDirectory(volume)
 	} else if source.EmptyDirectory != nil {
-		vol = createEmptyDirectory(volume, podID)
+		vol = createEmptyDirectory(volume, podID, rootDir)
 	} else {
 		return nil, errors.New("Unsupported volume type.")
 	}

pkg/volume/volume_test.go

@@ -38,9 +38,10 @@ func TestCreateVolumes(t *testing.T) {
 		},
 	}
 	fakePodID := "my-id"
-	expectedPaths := []string{"/dir/path", "/exports/my-id/empty-dir"}
+	rootDir := "/var/lib/kubelet"
+	expectedPaths := []string{"/dir/path", "/var/lib/kubelet/my-id/volumes/empty/empty-dir"}
 	for i, volume := range volumes {
-		extVolume, _ := CreateVolume(&volume, fakePodID)
+		extVolume, _ := CreateVolume(&volume, fakePodID, rootDir)
 		expectedPath := expectedPaths[i]
 		path := extVolume.GetPath()
 		if expectedPath != path {