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Add new refcounter for iSCSI volumes

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This commit is contained in:
Fabio Bertinatto 2019-07-22 14:25:39 +02:00
parent da3daf2e8a
commit 0007c2abd4
3 changed files with 72 additions and 66 deletions
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1
pkg/volume/iscsi/BUILD
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@ -18,6 +18,7 @@ go_library(
importpath = "k8s.io/kubernetes/pkg/volume/iscsi",
deps = [
"//pkg/features:go_default_library",
"//pkg/kubelet/config:go_default_library",
"//pkg/util/mount:go_default_library",
"//pkg/volume:go_default_library",
"//pkg/volume/util:go_default_library",

106
pkg/volume/iscsi/iscsi_util.go
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@ -19,6 +19,7 @@ package iscsi
import (
"encoding/json"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"regexp"
@ -26,10 +27,11 @@ import (
"strings"
"time"
"k8s.io/api/core/v1"
v1 "k8s.io/api/core/v1"
utilfeature "k8s.io/apiserver/pkg/util/feature"
"k8s.io/klog"
"k8s.io/kubernetes/pkg/features"
"k8s.io/kubernetes/pkg/kubelet/config"
"k8s.io/kubernetes/pkg/util/mount"
"k8s.io/kubernetes/pkg/volume"
volumeutil "k8s.io/kubernetes/pkg/volume/util"
@ -162,30 +164,6 @@ func waitForPathToExistInternal(devicePath *string, maxRetries int, deviceTransp
return false
}
// getDevicePrefixRefCount: given a prefix of device path, find its reference count from /proc/mounts
// returns the reference count to the device and error code
// for services like iscsi construct multiple device paths with the same prefix pattern.
// this function aggregates all references to a service based on the prefix pattern
// More specifically, this prefix semantics is to aggregate disk paths that belong to the same iSCSI target/iqn pair.
// an iSCSI target could expose multiple LUNs through the same IQN, and Linux iSCSI initiator creates disk paths that start the same prefix but end with different LUN number
// When we decide whether it is time to logout a target, we have to see if none of the LUNs are used any more.
// That's where the prefix based ref count kicks in. If we only count the disks using exact match, we could log other disks out.
func getDevicePrefixRefCount(mounter mount.Interface, deviceNamePrefix string) (int, error) {
mps, err := mounter.List()
if err != nil {
return -1, err
}
// Find the number of references to the device.
refCount := 0
for i := range mps {
if strings.HasPrefix(mps[i].Path, deviceNamePrefix) {
refCount++
}
}
return refCount, nil
}
// make a directory like /var/lib/kubelet/plugins/kubernetes.io/iscsi/iface_name/portal-some_iqn-lun-lun_id
func makePDNameInternal(host volume.VolumeHost, portal string, iqn string, lun string, iface string) string {
return filepath.Join(host.GetPluginDir(iscsiPluginName), "iface-"+iface, portal+"-"+iqn+"-lun-"+lun)
@ -612,7 +590,7 @@ func (util *ISCSIUtil) DetachDisk(c iscsiDiskUnmounter, mntPath string) error {
}
// if device is no longer used, see if need to logout the target
device, prefix, err := extractDeviceAndPrefix(mntPath)
device, _, err := extractDeviceAndPrefix(mntPath)
if err != nil {
return err
}
@ -650,17 +628,16 @@ func (util *ISCSIUtil) DetachDisk(c iscsiDiskUnmounter, mntPath string) error {
c.plugin.targetLocks.LockKey(iqn)
defer c.plugin.targetLocks.UnlockKey(iqn)
// if device is no longer used, see if need to logout the target
refCount, err := getDevicePrefixRefCount(c.mounter, prefix)
if err != nil || refCount != 0 {
return nil
}
portals := removeDuplicate(bkpPortal)
if len(portals) == 0 {
return fmt.Errorf("iscsi detach disk: failed to detach iscsi disk. Couldn't get connected portals from configurations")
}
// If device is no longer used, see if need to logout the target
if isSessionBusy(c.iscsiDisk.plugin.host, portals[0], iqn) {
return nil
}
err = util.detachISCSIDisk(c.exec, portals, iqn, iface, volName, initiatorName, found)
if err != nil {
return fmt.Errorf("failed to finish detachISCSIDisk, err: %v", err)
@ -718,10 +695,16 @@ func (util *ISCSIUtil) DetachBlockISCSIDisk(c iscsiDiskUnmapper, mapPath string)
if _, err = os.Stat(devicePath); err != nil {
return fmt.Errorf("failed to validate devicePath: %s", devicePath)
}
// check if the dev is using mpio and if so mount it via the dm-XX device
if mappedDevicePath := c.deviceUtil.FindMultipathDeviceForDevice(devicePath); mappedDevicePath != "" {
devicePath = mappedDevicePath
// Lock the target while we determine if we can safely log out or not
c.plugin.targetLocks.LockKey(iqn)
defer c.plugin.targetLocks.UnlockKey(iqn)
// If device is no longer used, see if need to logout the target
if isSessionBusy(c.iscsiDisk.plugin.host, portals[0], iqn) {
return nil
}
// Detach a volume from kubelet node
err = util.detachISCSIDisk(c.exec, portals, iqn, iface, volName, initiatorName, found)
if err != nil {
@ -897,3 +880,56 @@ func cloneIface(b iscsiDiskMounter) error {
}
return lastErr
}
// isSessionBusy determines if the iSCSI session is busy by counting both FS and block volumes in use.
func isSessionBusy(host volume.VolumeHost, portal, iqn string) bool {
fsDir := host.GetPluginDir(iscsiPluginName)
countFS, err := getVolCount(fsDir, portal, iqn)
if err != nil {
klog.Errorf("iscsi: could not determine FS volumes in use: %v", err)
return true
}
blockDir := host.GetVolumeDevicePluginDir(iscsiPluginName)
countBlock, err := getVolCount(blockDir, portal, iqn)
if err != nil {
klog.Errorf("iscsi: could not determine block volumes in use: %v", err)
return true
}
return countFS+countBlock > 1
}
// getVolCount returns the number of volumes in use by the kubelet.
// It does so by counting the number of directories prefixed by the given portal and IQN.
func getVolCount(dir, portal, iqn string) (int, error) {
// The topmost dirs are named after the ifaces, e.g., iface-default or iface-127.0.0.1:3260:pv0
contents, err := ioutil.ReadDir(dir)
if err != nil {
return 0, err
}
// Inside each iface dir, we look for volume dirs prefixed by the given
// portal + iqn, e.g., 127.0.0.1:3260-iqn.2003-01.io.k8s:e2e.volume-1-lun-2
var counter int
for _, c := range contents {
if !c.IsDir() || c.Name() == config.DefaultKubeletVolumeDevicesDirName {
continue
}
mounts, err := ioutil.ReadDir(filepath.Join(dir, c.Name()))
if err != nil {
return 0, err
}
for _, m := range mounts {
volumeMount := m.Name()
prefix := portal + "-" + iqn
if strings.HasPrefix(volumeMount, prefix) {
counter++
}
}
}
return counter, nil
}

31
pkg/volume/iscsi/iscsi_util_test.go
View File

@ -28,37 +28,6 @@ import (
"k8s.io/kubernetes/pkg/volume"
)
func TestGetDevicePrefixRefCount(t *testing.T) {
fm := &mount.FakeMounter{
MountPoints: []mount.MountPoint{
{Device: "/dev/sdb",
Path: "/127.0.0.1:3260-iqn.2014-12.com.example:test.tgt00-lun-0"},
{Device: "/dev/sdb",
Path: "/127.0.0.1:3260-iqn.2014-12.com.example:test.tgt00-lun-1"},
{Device: "/dev/sdb",
Path: "/127.0.0.1:3260-iqn.2014-12.com.example:test.tgt00-lun-2"},
{Device: "/dev/sdb",
Path: "/127.0.0.1:3260-iqn.2014-12.com.example:test.tgt00-lun-3"},
},
}
tests := []struct {
devicePrefix string
expectedRefs int
}{
{
"/127.0.0.1:3260-iqn.2014-12.com.example:test.tgt00",
4,
},
}
for i, test := range tests {
if refs, err := getDevicePrefixRefCount(fm, test.devicePrefix); err != nil || test.expectedRefs != refs {
t.Errorf("%d. GetDevicePrefixRefCount(%s) = %d, %v; expected %d, nil", i, test.devicePrefix, refs, err, test.expectedRefs)
}
}
}
func TestExtractDeviceAndPrefix(t *testing.T) {
devicePath := "127.0.0.1:3260-iqn.2014-12.com.example:test.tgt00"
mountPrefix := "/var/lib/kubelet/plugins/kubernetes.io/iscsi/iface-default/" + devicePath