add iscsi volume plugin

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

pkg/volume/iscsi/disk_manager.go

@@ -0,0 +1,112 @@
+/*
+Copyright 2015 Google Inc. All rights reserved.
+
+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 iscsi
+
+import (
+	"os"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util/mount"
+	"github.com/golang/glog"
+)
+
+// Abstract interface to disk operations.
+type diskManager interface {
+	MakeGlobalPDName(disk iscsiDisk) string
+	// Attaches the disk to the kubelet's host machine.
+	AttachDisk(disk iscsiDisk) error
+	// Detaches the disk from the kubelet's host machine.
+	DetachDisk(disk iscsiDisk, mntPath string) error
+}
+
+// utility to mount a disk based filesystem
+func diskSetUp(manager diskManager, disk iscsiDisk, volPath string, mounter mount.Interface) error {
+	globalPDPath := manager.MakeGlobalPDName(disk)
+	// TODO: handle failed mounts here.
+	mountpoint, err := mounter.IsMountPoint(volPath)
+
+	if err != nil && !os.IsNotExist(err) {
+		glog.Errorf("cannot validate mountpoint: %s", volPath)
+		return err
+	}
+	if mountpoint {
+		return nil
+	}
+	if err := manager.AttachDisk(disk); err != nil {
+		glog.Errorf("failed to attach disk")
+		return err
+	}
+
+	if err := os.MkdirAll(volPath, 0750); err != nil {
+		glog.Errorf("failed to mkdir:%s", volPath)
+		return err
+	}
+	// Perform a bind mount to the full path to allow duplicate mounts of the same disk.
+	flags := uintptr(0)
+	if disk.readOnly {
+		flags = mount.FlagReadOnly
+	}
+	err = mounter.Mount(globalPDPath, volPath, "", mount.FlagBind|flags, "")
+	if err != nil {
+		glog.Errorf("failed to bind mount:%s", globalPDPath)
+		return err
+	}
+	return nil
+}
+
+// utility to tear down a disk based filesystem
+func diskTearDown(manager diskManager, disk iscsiDisk, volPath string, mounter mount.Interface) error {
+	mountpoint, err := mounter.IsMountPoint(volPath)
+	if err != nil {
+		glog.Errorf("cannot validate mountpoint %s", volPath)
+		return err
+	}
+	if !mountpoint {
+		return os.Remove(volPath)
+	}
+
+	refs, err := mount.GetMountRefs(mounter, volPath)
+	if err != nil {
+		glog.Errorf("failed to get reference count %s", volPath)
+		return err
+	}
+	if err := mounter.Unmount(volPath, 0); err != nil {
+		glog.Errorf("failed to umount %s", volPath)
+		return err
+	}
+	// If len(refs) is 1, then all bind mounts have been removed, and the
+	// remaining reference is the global mount. It is safe to detach.
+	if len(refs) == 1 {
+		mntPath := refs[0]
+		if err := manager.DetachDisk(disk, mntPath); err != nil {
+			glog.Errorf("failed to detach disk from %s", mntPath)
+			return err
+		}
+	}
+
+	mountpoint, mntErr := mounter.IsMountPoint(volPath)
+	if mntErr != nil {
+		glog.Errorf("isMountpoint check failed: %v", mntErr)
+		return err
+	}
+	if !mountpoint {
+		if err := os.Remove(volPath); err != nil {
+			return err
+		}
+	}
+	return nil
+
+}