Cherry pick #14044 to release-1.1

examples/rbd/README.md

@@ -7,7 +7,7 @@
 
 Install Ceph on the Kubernetes host. For example, on Fedora 21
 
-    # yum -y install ceph
+    # yum -y install ceph-common
 
 If you don't have a Ceph cluster, you can set up a [containerized Ceph cluster](https://github.com/rootfs/docker-ceph)
 
@@ -26,7 +26,14 @@ Once you have installed Ceph and new Kubernetes, you can create a pod based on m
 
 # Use Ceph Authentication Secret
 
-If Ceph authentication secret is provided, the secret should be first be base64 encoded, then encoded string is placed in a secret yaml. An example yaml is provided [here](secret/ceph-secret.yaml). Then post the secret through ```kubectl``` in the following command.
+If Ceph authentication secret is provided, the secret should be first be *base64 encoded*, then encoded string is placed in a secret yaml. For example, getting Ceph user `kube`'s base64 encoded secret can use the following command:
+
+```console
+  # grep key /etc/ceph/ceph.client.kube.keyring |awk '{printf "%s", $NF}'|base64
+QVFBTWdYaFZ3QkNlRGhBQTlubFBhRnlmVVNhdEdENGRyRldEdlE9PQ==
+```
+
+An example yaml is provided [here](secret/ceph-secret.yaml). Then post the secret through ```kubectl``` in the following command.
 
 ```console
     # kubectl create -f examples/rbd/secret/ceph-secret.yaml

pkg/volume/rbd/rbd.go

@@ -131,7 +131,7 @@ func (plugin *rbdPlugin) newBuilderInternal(spec *volume.Spec, podUID types.UID,
 			Pool:     pool,
 			ReadOnly: readOnly,
 			manager:  manager,
-			mounter:  mounter,
+			mounter:  &mount.SafeFormatAndMount{mounter, exec.New()},
 			plugin:   plugin,
 		},
 		Mon:     source.CephMonitors,

pkg/volume/rbd/rbd_util.go

@@ -25,31 +25,63 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"io/ioutil"
 	"math/rand"
 	"os"
 	"path"
+	"regexp"
 	"strings"
 	"time"
 
 	"github.com/golang/glog"
+	"k8s.io/kubernetes/pkg/util/exec"
 	"k8s.io/kubernetes/pkg/util/mount"
 	"k8s.io/kubernetes/pkg/util/node"
 	"k8s.io/kubernetes/pkg/volume"
 )
 
+// search /sys/bus for rbd device that matches given pool and image
+func getDevFromImageAndPool(pool, image string) (string, bool) {
+	// /sys/bus/rbd/devices/X/name and /sys/bus/rbd/devices/X/pool
+	sys_path := "/sys/bus/rbd/devices"
+	if dirs, err := ioutil.ReadDir(sys_path); err == nil {
+		for _, f := range dirs {
+			// pool and name format:
+			// see rbd_pool_show() and rbd_name_show() at
+			// https://github.com/torvalds/linux/blob/master/drivers/block/rbd.c
+			name := f.Name()
+			// first match pool, then match name
+			po := path.Join(sys_path, name, "pool")
+			img := path.Join(sys_path, name, "name")
+			exe := exec.New()
+			out, err := exe.Command("cat", po, img).CombinedOutput()
+			if err != nil {
+				continue
+			}
+			matched, err := regexp.MatchString("^"+pool+"\n"+image+"\n$", string(out))
+			if err != nil || !matched {
+				continue
+			}
+			// found a match, check if device exists
+			devicePath := "/dev/rbd" + name
+			if _, err := os.Lstat(devicePath); err == nil {
+				return devicePath, true
+			}
+		}
+	}
+	return "", false
+}
+
 // stat a path, if not exists, retry maxRetries times
-func waitForPathToExist(devicePath string, maxRetries int) bool {
+func waitForPath(pool, image string, maxRetries int) (string, bool) {
 	for i := 0; i < maxRetries; i++ {
-		_, err := os.Stat(devicePath)
-		if err == nil {
-			return true
-		}
-		if err != nil && !os.IsNotExist(err) {
-			return false
+		devicePath, found := getDevFromImageAndPool(pool, image)
+		if found {
+			return devicePath, true
 		}
 		time.Sleep(time.Second)
 	}
-	return false
+	return "", false
 }
 
 // make a directory like /var/lib/kubelet/plugins/kubernetes.io/pod/rbd/pool-image-image
@@ -178,9 +210,9 @@ func (util *RBDUtil) defencing(c rbdCleaner) error {
 
 func (util *RBDUtil) AttachDisk(b rbdBuilder) error {
 	var err error
-	devicePath := strings.Join([]string{"/dev/rbd", b.Pool, b.Image}, "/")
-	exist := waitForPathToExist(devicePath, 1)
-	if !exist {
+
+	devicePath, found := waitForPath(b.Pool, b.Image, 1)
+	if !found {
 		// modprobe
 		_, err = b.plugin.execCommand("modprobe", []string{"rbd"})
 		if err != nil {
@@ -209,8 +241,8 @@ func (util *RBDUtil) AttachDisk(b rbdBuilder) error {
 	if err != nil {
 		return err
 	}
-	exist = waitForPathToExist(devicePath, 10)
-	if !exist {
+	devicePath, found = waitForPath(b.Pool, b.Image, 10)
+	if !found {
 		return errors.New("Could not map image: Timeout after 10s")
 	}
 	// mount it
@@ -230,6 +262,8 @@ func (util *RBDUtil) AttachDisk(b rbdBuilder) error {
 
 	// fence off other mappers
 	if err := util.fencing(b); err != nil {
+		// rbd unmap before exit
+		b.plugin.execCommand("rbd", []string{"unmap", devicePath})
 		return fmt.Errorf("rbd: image %s is locked by other nodes", b.Image)
 	}
 	// rbd lock remove needs ceph and image config