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Add wait loop for multipath devices to appear

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It takes a variable amount of time for the multipath daemon
to create /dev/dm-XX in response to new LUNs being discovered.
The old iscsi_util code only discovered the multipath device
if it was created quickly enough, but in a significant number
of cases, kubelet would grab one of the individual paths and
put a filesystem it on before multipathd could construct a
multipath device.

This change waits for the multipath device to get created for
up to 10 seconds, but only if the PV actually had more than
one portal.
This commit is contained in:
Ben Swartzlander 2018-07-06 16:04:27 -04:00
parent 81c6b735fa
commit 39e52ddae5
1 changed files with 40 additions and 13 deletions
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51
pkg/volume/iscsi/iscsi_util.go
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@ -241,6 +241,31 @@ func scanOneLun(hostNumber int, lunNumber int) error {
return nil
}
func waitForMultiPathToExist(devicePaths []string, maxRetries int, deviceUtil volumeutil.DeviceUtil) string {
if 0 == len(devicePaths) {
return ""
}
for i := 0; i < maxRetries; i++ {
for _, path := range devicePaths {
// There shouldnt be any empty device paths. However adding this check
// for safer side to avoid the possibility of an empty entry.
if path == "" {
continue
}
// check if the dev is using mpio and if so mount it via the dm-XX device
if mappedDevicePath := deviceUtil.FindMultipathDeviceForDevice(path); mappedDevicePath != "" {
return mappedDevicePath
}
}
if i == maxRetries-1 {
break
}
time.Sleep(time.Second)
}
return ""
}
// AttachDisk returns devicePath of volume if attach succeeded otherwise returns error
func (util *ISCSIUtil) AttachDisk(b iscsiDiskMounter) (string, error) {
var devicePath string
@ -381,19 +406,21 @@ func (util *ISCSIUtil) AttachDisk(b iscsiDiskMounter) (string, error) {
glog.Errorf("iscsi: last error occurred during iscsi init:\n%v", lastErr)
}
//Make sure we use a valid devicepath to find mpio device.
// Try to find a multipath device for the volume
if 1 < len(bkpPortal) {
// If the PV has 2 or more portals, wait up to 10 seconds for the multipath
// device to appear
devicePath = waitForMultiPathToExist(devicePaths, 10, b.deviceUtil)
} else {
// For PVs with 1 portal, just try one time to find the multipath device. This
// avoids a long pause when the multipath device will never get created, and
// matches legacy behavior.
devicePath = waitForMultiPathToExist(devicePaths, 1, b.deviceUtil)
}
// When no multipath device is found, just use the first (and presumably only) device
if devicePath == "" {
devicePath = devicePaths[0]
for _, path := range devicePaths {
// There shouldnt be any empty device paths. However adding this check
// for safer side to avoid the possibility of an empty entry.
if path == "" {
continue
}
// check if the dev is using mpio and if so mount it via the dm-XX device
if mappedDevicePath := b.deviceUtil.FindMultipathDeviceForDevice(path); mappedDevicePath != "" {
devicePath = mappedDevicePath
break
}
}
glog.V(5).Infof("iscsi: AttachDisk devicePath: %s", devicePath)