support rbd-nbd

Signed-off-by: Huamin Chen <hchen@redhat.com>

deploy/rbd/docker/Dockerfile

@@ -4,7 +4,7 @@ LABEL description="RBD CSI Plugin"
 
 ENV CEPH_VERSION "mimic"
 RUN yum  install -y centos-release-ceph && \
-    yum install -y ceph-common e2fsprogs && \ 
+    yum install -y ceph-common e2fsprogs rbd-nbd && \ 
     yum clean all
 
 COPY rbdplugin /rbdplugin

deploy/rbd/kubernetes/csi-rbdplugin.yaml

@@ -34,7 +34,7 @@ spec:
               mountPath: /var/lib/kubelet/plugins/csi-rbdplugin
             - name: registration-dir
               mountPath: /registration
-        - name: csi-rbdplugin 
+        - name: csi-rbdplugin
           securityContext:
             privileged: true
             capabilities:
@@ -47,6 +47,8 @@ spec:
             - "--v=5"
             - "--drivername=csi-rbdplugin"
           env:
+            - name: HOST_ROOTFS
+              value: "/host"
             - name: NODE_ID
               valueFrom:
                 fieldRef:
@@ -62,6 +64,8 @@ spec:
               mountPropagation: "Bidirectional"
             - mountPath: /dev
               name: host-dev
+            - mountPath: /host
+              name: host-rootfs            
             - mountPath: /sys
               name: host-sys
             - mountPath: /lib/modules
@@ -87,6 +91,9 @@ spec:
         - name: host-dev
           hostPath:
             path: /dev
+        - name: host-rootfs
+          hostPath:
+            path: /            
         - name: host-sys
           hostPath:
             path: /sys

pkg/rbd/rbd_attach.go

@@ -0,0 +1,303 @@
+/*
+Copyright 2018 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package rbd
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/golang/glog"
+	"k8s.io/apimachinery/pkg/util/wait"
+)
+
+const (
+	envHostRootFS = "HOST_ROOTFS"
+)
+
+var (
+	hostRootFS = "/"
+	useNBD     = false
+)
+
+func init() {
+	host := os.Getenv(envHostRootFS)
+	if len(host) > 0 {
+		hostRootFS = host
+	}
+	useNBD = checkRbdNbdTools()
+}
+
+func getDevFromImageAndPool(pool, image string) (string, bool) {
+	device, found := getRbdDevFromImageAndPool(pool, image)
+	if found {
+		return device, true
+	}
+	device, found = getNbdDevFromImageAndPool(pool, image)
+	if found {
+		return device, true
+	}
+	return "", false
+}
+
+// Search /sys/bus for rbd device that matches given pool and image.
+func getRbdDevFromImageAndPool(pool string, 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.
+			poolFile := path.Join(sys_path, name, "pool")
+			poolBytes, err := ioutil.ReadFile(poolFile)
+			if err != nil {
+				glog.V(4).Infof("error reading %s: %v", poolFile, err)
+				continue
+			}
+			if strings.TrimSpace(string(poolBytes)) != pool {
+				glog.V(4).Infof("device %s is not %q: %q", name, pool, string(poolBytes))
+				continue
+			}
+			imgFile := path.Join(sys_path, name, "name")
+			imgBytes, err := ioutil.ReadFile(imgFile)
+			if err != nil {
+				glog.V(4).Infof("error reading %s: %v", imgFile, err)
+				continue
+			}
+			if strings.TrimSpace(string(imgBytes)) != image {
+				glog.V(4).Infof("device %s is not %q: %q", name, image, string(imgBytes))
+				continue
+			}
+			// Found a match, check if device exists.
+			devicePath := "/dev/rbd" + name
+			if _, err := os.Lstat(devicePath); err == nil {
+				return devicePath, true
+			}
+		}
+	}
+	return "", false
+}
+
+func getMaxNbds() (int, error) {
+
+	// the max number of nbd devices may be found in maxNbdsPath
+	// we will check sysfs for possible nbd devices even if this is not available
+	maxNbdsPath := "/sys/module/nbd/parameters/nbds_max"
+	_, err := os.Lstat(maxNbdsPath)
+	if err != nil {
+		return 0, fmt.Errorf("rbd-nbd: failed to retrieve max_nbds from %s err: %q", maxNbdsPath, err)
+	}
+
+	glog.V(4).Infof("found nbds max parameters file at %s", maxNbdsPath)
+
+	maxNbdBytes, err := ioutil.ReadFile(maxNbdsPath)
+	if err != nil {
+		return 0, fmt.Errorf("rbd-nbd: failed to read max_nbds from %s err: %q", maxNbdsPath, err)
+	}
+
+	maxNbds, err := strconv.Atoi(strings.TrimSpace(string(maxNbdBytes)))
+	if err != nil {
+		return 0, fmt.Errorf("rbd-nbd: failed to read max_nbds err: %q", err)
+	}
+
+	glog.V(4).Infof("rbd-nbd: max_nbds: %d", maxNbds)
+	return maxNbds, nil
+}
+
+// Locate any existing rbd-nbd process mapping given a <pool, image>.
+// Recent versions of rbd-nbd tool can correctly provide this info using list-mapped
+// but older versions of list-mapped don't.
+// The implementation below peeks at the command line of nbd bound processes
+// to figure out any mapped images.
+func getNbdDevFromImageAndPool(pool string, image string) (string, bool) {
+	// nbd module exports the pid of serving process in sysfs
+	basePath := "/sys/block/nbd"
+	// Do not change imgPath format - some tools like rbd-nbd are strict about it.
+	imgPath := fmt.Sprintf("%s/%s", pool, image)
+
+	maxNbds, maxNbdsErr := getMaxNbds()
+	if maxNbdsErr != nil {
+		glog.V(4).Infof("error reading nbds_max %v", maxNbdsErr)
+		return "", false
+	}
+
+	for i := 0; i < maxNbds; i++ {
+		nbdPath := basePath + strconv.Itoa(i)
+		_, err := os.Lstat(nbdPath)
+		if err != nil {
+			glog.V(4).Infof("error reading nbd info directory %s: %v", nbdPath, err)
+			continue
+		}
+		pidBytes, err := ioutil.ReadFile(path.Join(nbdPath, "pid"))
+		if err != nil {
+			glog.V(5).Infof("did not find valid pid file in dir %s: %v", nbdPath, err)
+			continue
+		}
+		cmdlineFileName := path.Join(hostRootFS, "/proc", strings.TrimSpace(string(pidBytes)), "cmdline")
+		rawCmdline, err := ioutil.ReadFile(cmdlineFileName)
+		if err != nil {
+			glog.V(4).Infof("failed to read cmdline file %s: %v", cmdlineFileName, err)
+			continue
+		}
+		cmdlineArgs := strings.FieldsFunc(string(rawCmdline), func(r rune) bool {
+			return r == '\u0000'
+		})
+		// Check if this process is mapping a rbd device.
+		// Only accepted pattern of cmdline is from execRbdMap:
+		// rbd-nbd map pool/image ...
+		if len(cmdlineArgs) < 3 || cmdlineArgs[0] != "rbd-nbd" || cmdlineArgs[1] != "map" {
+			glog.V(4).Infof("nbd device %s is not used by rbd", nbdPath)
+			continue
+		}
+		if cmdlineArgs[2] != imgPath {
+			glog.V(4).Infof("rbd-nbd device %s did not match expected image path: %s with path found: %s",
+				nbdPath, imgPath, cmdlineArgs[2])
+			continue
+		}
+		devicePath := path.Join("/dev", "nbd"+strconv.Itoa(i))
+		if _, err := os.Lstat(devicePath); err != nil {
+			glog.Warningf("Stat device %s for imgpath %s failed %v", devicePath, imgPath, err)
+			continue
+		}
+		return devicePath, true
+	}
+	return "", false
+}
+
+// Stat a path, if it doesn't exist, retry maxRetries times.
+func waitForPath(pool, image string, maxRetries int, useNbdDriver bool) (string, bool) {
+	for i := 0; i < maxRetries; i++ {
+		if i != 0 {
+			time.Sleep(time.Second)
+		}
+		if useNbdDriver {
+			if devicePath, found := getNbdDevFromImageAndPool(pool, image); found {
+				return devicePath, true
+			}
+		} else {
+			if devicePath, found := getRbdDevFromImageAndPool(pool, image); found {
+				return devicePath, true
+			}
+		}
+	}
+	return "", false
+}
+
+// Check if rbd-nbd tools are installed.
+func checkRbdNbdTools() bool {
+	_, err := execCommand("modprobe", []string{"nbd"})
+	if err != nil {
+		glog.V(3).Infof("rbd-nbd: nbd modprobe failed with error %v", err)
+		return false
+	}
+	if _, err := execCommand("rbd-nbd", []string{"--version"}); err != nil {
+		glog.V(3).Infof("rbd-nbd: running rbd-nbd -h failed with error %v", err)
+		return false
+	}
+	glog.V(3).Infof("rbd-nbd tools were found.")
+	return true
+}
+
+func attachRBDImage(volOptions *rbdVolume, userId string, credentials map[string]string) (string, error) {
+	var err error
+	var output []byte
+
+	image := volOptions.VolName
+	imagePath := fmt.Sprintf("%s/%s", volOptions.Pool, image)
+
+	cmdName := "rbd"
+	moduleName := "rbd"
+	if useNBD {
+		cmdName = "rbd-nbd"
+		moduleName = "nbd"
+	}
+	devicePath, found := waitForPath(volOptions.Pool, image, 1, useNBD)
+	if !found {
+		attachdetachMutex.LockKey(string(volOptions.Pool + image))
+		defer attachdetachMutex.UnlockKey(string(imagePath))
+
+		_, err = execCommand("modprobe", []string{moduleName})
+		if err != nil {
+			glog.Warningf("rbd: failed to load rbd kernel module:%v", err)
+		}
+
+		backoff := wait.Backoff{
+			Duration: rbdImageWatcherInitDelay,
+			Factor:   rbdImageWatcherFactor,
+			Steps:    rbdImageWatcherSteps,
+		}
+		err := wait.ExponentialBackoff(backoff, func() (bool, error) {
+			used, rbdOutput, err := rbdStatus(volOptions, userId, credentials)
+			if err != nil {
+				return false, fmt.Errorf("fail to check rbd image status with: (%v), rbd output: (%s)", err, rbdOutput)
+			}
+			return !used, nil
+		})
+		// return error if rbd image has not become available for the specified timeout
+		if err == wait.ErrWaitTimeout {
+			return "", fmt.Errorf("rbd image %s is still being used", imagePath)
+		}
+		// return error if any other errors were encountered during wating for the image to becme avialble
+		if err != nil {
+			return "", err
+		}
+
+		glog.V(3).Infof("rbd: map mon %s", volOptions.Monitors)
+		key, err := getRBDKey(userId, credentials)
+		if err != nil {
+			return "", err
+		}
+		output, err = execCommand(cmdName, []string{
+			"map", imagePath, "--id", userId, "-m", volOptions.Monitors, "--key=" + key})
+		if err != nil {
+			glog.Warningf("rbd: map error %v, rbd output: %s", err, string(output))
+			return "", fmt.Errorf("rbd: map failed %v, rbd output: %s", err, string(output))
+		}
+		devicePath, found = waitForPath(volOptions.Pool, image, 10, useNBD)
+		if !found {
+			return "", fmt.Errorf("Could not map image %s, Timeout after 10s", imagePath)
+		}
+	}
+
+	return devicePath, nil
+}
+
+func detachRBDDevice(devicePath string) error {
+	var err error
+	var output []byte
+
+	glog.V(3).Infof("rbd: unmap device %s", devicePath)
+
+	cmdName := "rbd"
+	if strings.HasPrefix(devicePath, "/dev/nbd") {
+		cmdName = "rbd-nbd"
+	}
+
+	output, err = execCommand(cmdName, []string{"unmap", devicePath})
+	if err != nil {
+		return fmt.Errorf("rbd: unmap failed %v, rbd output: %s", err, string(output))
+	}
+
+	return nil
+}

pkg/rbd/rbd_util.go

@@ -19,7 +19,6 @@ package rbd
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path"
@@ -28,7 +27,6 @@ import (
 
 	"github.com/golang/glog"
 	"k8s.io/apimachinery/pkg/util/sets"
-	"k8s.io/apimachinery/pkg/util/wait"
 	"k8s.io/kubernetes/pkg/util/keymutex"
 )
 
@@ -264,129 +262,6 @@ func hasSnapshotFeature(imageFeatures string) bool {
 	return false
 }
 
-func attachRBDImage(volOptions *rbdVolume, userId string, credentials map[string]string) (string, error) {
-	var err error
-	var output []byte
-
-	image := volOptions.VolName
-	devicePath, found := waitForPath(volOptions.Pool, image, 1)
-	if !found {
-		attachdetachMutex.LockKey(string(volOptions.Pool + image))
-		defer attachdetachMutex.UnlockKey(string(volOptions.Pool + image))
-
-		_, err = execCommand("modprobe", []string{"rbd"})
-		if err != nil {
-			glog.Warningf("rbd: failed to load rbd kernel module:%v", err)
-		}
-
-		backoff := wait.Backoff{
-			Duration: rbdImageWatcherInitDelay,
-			Factor:   rbdImageWatcherFactor,
-			Steps:    rbdImageWatcherSteps,
-		}
-		err := wait.ExponentialBackoff(backoff, func() (bool, error) {
-			used, rbdOutput, err := rbdStatus(volOptions, userId, credentials)
-			if err != nil {
-				return false, fmt.Errorf("fail to check rbd image status with: (%v), rbd output: (%s)", err, rbdOutput)
-			}
-			return !used, nil
-		})
-		// return error if rbd image has not become available for the specified timeout
-		if err == wait.ErrWaitTimeout {
-			return "", fmt.Errorf("rbd image %s/%s is still being used", volOptions.Pool, image)
-		}
-		// return error if any other errors were encountered during wating for the image to becme avialble
-		if err != nil {
-			return "", err
-		}
-
-		glog.V(1).Infof("rbd: map mon %s", volOptions.Monitors)
-		key, err := getRBDKey(userId, credentials)
-		if err != nil {
-			return "", err
-		}
-
-		output, err = execCommand("rbd", []string{
-			"map", image, "--pool", volOptions.Pool, "--id", userId, "-m", volOptions.Monitors, "--key=" + key})
-		if err != nil {
-			glog.V(1).Infof("rbd: map error %v, rbd output: %s", err, string(output))
-			return "", fmt.Errorf("rbd: map failed %v, rbd output: %s", err, string(output))
-		}
-		devicePath, found = waitForPath(volOptions.Pool, image, 10)
-		if !found {
-			return "", fmt.Errorf("Could not map image %s/%s, Timeout after 10s", volOptions.Pool, image)
-		}
-	}
-
-	return devicePath, nil
-}
-
-func detachRBDDevice(devicePath string) error {
-	var err error
-	var output []byte
-
-	glog.V(3).Infof("rbd: unmap device %s", devicePath)
-
-	output, err = execCommand("rbd", []string{"unmap", devicePath})
-	if err != nil {
-		return fmt.Errorf("rbd: unmap failed %v, rbd output: %s", err, string(output))
-	}
-
-	return nil
-}
-
-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 {
-			name := f.Name()
-			// first match pool, then match name
-			poolFile := path.Join(sys_path, name, "pool")
-			poolBytes, err := ioutil.ReadFile(poolFile)
-			if err != nil {
-				glog.V(4).Infof("Error reading %s: %v", poolFile, err)
-				continue
-			}
-			if strings.TrimSpace(string(poolBytes)) != pool {
-				glog.V(4).Infof("Device %s is not %q: %q", name, pool, string(poolBytes))
-				continue
-			}
-			imgFile := path.Join(sys_path, name, "name")
-			imgBytes, err := ioutil.ReadFile(imgFile)
-			if err != nil {
-				glog.V(4).Infof("Error reading %s: %v", imgFile, err)
-				continue
-			}
-			if strings.TrimSpace(string(imgBytes)) != image {
-				glog.V(4).Infof("Device %s is not %q: %q", name, image, string(imgBytes))
-				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 waitForPath(pool, image string, maxRetries int) (string, bool) {
-	for i := 0; i < maxRetries; i++ {
-		devicePath, found := getDevFromImageAndPool(pool, image)
-		if found {
-			return devicePath, true
-		}
-		if i == maxRetries-1 {
-			break
-		}
-		time.Sleep(time.Second)
-	}
-	return "", false
-}
-
 func persistVolInfo(image string, persistentStoragePath string, volInfo *rbdVolume) error {
 	file := path.Join(persistentStoragePath, image+".json")
 	fp, err := os.Create(file)