ceph-csi/internal/rbd/rbd_journal.go
Madhu Rajanna e3a63029a3 rbd: Implement snapshot and clone from snapshot
This Adds a support for create,delete snapshot
and creating a new rbd image from the snapshot.

* Create a snapshot

* Create a temporary snapshot from the parent volume
* Clone a new image from a temporary snapshot with options
  --rbd-default-clone-format 2 --image-feature layering,deep-flatten
* Delete temporary snapshot created
* Create a new snapshot from cloned image
* Check the image chain depth, if the Softlimit is reached Add a
  task Flatten the cloned image and return success. if the depth
  is reached hard limit Add a task Flatten the cloned image and
  return snapshot status ready as false

```bash
1) rbd snap create <RBD image for src k8s volume>@<random snap name>
2) rbd clone --rbd-default-clone-format 2 --image-feature
   layering,deep-flatten <RBD image for src k8s volume>@<random snap>
   <RBD image for temporary snap image>
3) rbd snap rm <RBD image for src k8s volume>@<random snap name>
4) rbd snap rm <RBD image for temporary snap image>@<random snap name>
5) check the depth, if the depth is greater than configured hard
   limit add a task to flatten the cloned image return snapshot status
   ready as false if the depth is greater than soft limit add a task
   to flatten the image and return success
```

* Create a clone from snapshot

* Clone a new image from the snapshot with user-provided options
* Check the depth(n) of the cloned image if n>=(hard limit)
  Add task to flatten the image and return ABORT (to avoid image leak)

```bash
1) rbd clone --rbd-default-clone-format 2 --image-feature
   <k8s dst vol config> <RBD image for temporary snap image>@<random snap name>
    <RBD image for k8s dst vol>
2) check the depth, if the depth is greater than configured hard limit
    add a task to flatten the cloned image return ABORT error if the depth is
    greater than soft limit add a task to flatten the image and return success
```

* Delete snapshot or pvc

* Move the temporary cloned image to the trash
* Add task to remove the image from the trash

```bash
1) rbd trash mv <cloned image>
2) ceph rbd task trash remove <cloned image>
```

With earlier implementation to delete the image, we used to add
a task to remove the image with new changes this cannot be done
as the image may contain snapshots or linking.so we will be
doing below steps to delete an image(this will be
applicable for both normal image and cloned image)

* Move the rbd image to the trash
* Add task to remove the image from the trash

```bash
1) rbd trash mv <image>
2) ceph rbd task trash remove <image>
```

Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>
2020-07-01 08:21:47 +00:00

447 lines
13 KiB
Go

/*
Copyright 2019 The Ceph-CSI 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 (
"context"
"fmt"
"github.com/ceph/ceph-csi/internal/util"
"github.com/pkg/errors"
"k8s.io/klog"
)
func validateNonEmptyField(field, fieldName, structName string) error {
if field == "" {
return fmt.Errorf("value '%s' in '%s' structure cannot be empty", fieldName, structName)
}
return nil
}
func validateRbdSnap(rbdSnap *rbdSnapshot) error {
var err error
if err = validateNonEmptyField(rbdSnap.RequestName, "RequestName", "rbdSnapshot"); err != nil {
return err
}
if err = validateNonEmptyField(rbdSnap.Monitors, "Monitors", "rbdSnapshot"); err != nil {
return err
}
if err = validateNonEmptyField(rbdSnap.Pool, "Pool", "rbdSnapshot"); err != nil {
return err
}
if err = validateNonEmptyField(rbdSnap.RbdImageName, "RbdImageName", "rbdSnapshot"); err != nil {
return err
}
if err = validateNonEmptyField(rbdSnap.ClusterID, "ClusterID", "rbdSnapshot"); err != nil {
return err
}
return err
}
func validateRbdVol(rbdVol *rbdVolume) error {
var err error
if err = validateNonEmptyField(rbdVol.RequestName, "RequestName", "rbdVolume"); err != nil {
return err
}
if err = validateNonEmptyField(rbdVol.Monitors, "Monitors", "rbdVolume"); err != nil {
return err
}
if err = validateNonEmptyField(rbdVol.Pool, "Pool", "rbdVolume"); err != nil {
return err
}
if err = validateNonEmptyField(rbdVol.ClusterID, "ClusterID", "rbdVolume"); err != nil {
return err
}
if rbdVol.VolSize == 0 {
return errors.New("value 'VolSize' in 'rbdVolume' structure cannot be 0")
}
return err
}
/*
checkSnapCloneExists, and its counterpart checkVolExists, function checks if
the passed in rbdSnapshot or rbdVolume exists on the backend.
**NOTE:** These functions manipulate the rados omaps that hold information
regarding volume names as requested by the CSI drivers. Hence, these need to be
invoked only when the respective CSI driver generated snapshot or volume name
based locks are held, as otherwise racy access to these omaps may end up
leaving them in an inconsistent state.
These functions need enough information about cluster and pool (ie, Monitors,
Pool, IDs filled in) to operate. They further require that the RequestName
element of the structure have a valid value to operate on and determine if the
said RequestName already exists on the backend.
These functions populate the snapshot or the image name, its attributes and the
CSI snapshot/volume ID for the same when successful.
These functions also cleanup omap reservations that are stale. I.e when omap
entries exist and backing images or snapshots are missing, or one of the omaps
exist and the next is missing. This is because, the order of omap creation and
deletion are inverse of each other, and protected by the request name lock, and
hence any stale omaps are leftovers from incomplete transactions and are hence
safe to garbage collect.
*/
func checkSnapCloneExists(ctx context.Context, parentVol *rbdVolume, rbdSnap *rbdSnapshot, cr *util.Credentials) (bool, error) {
err := validateRbdSnap(rbdSnap)
if err != nil {
return false, err
}
j, err := snapJournal.Connect(rbdSnap.Monitors, cr)
if err != nil {
return false, err
}
defer j.Destroy()
snapData, err := j.CheckReservation(ctx, rbdSnap.JournalPool,
rbdSnap.RequestName, rbdSnap.NamePrefix, rbdSnap.RbdImageName, "")
if err != nil {
return false, err
}
if snapData == nil {
return false, nil
}
snapUUID := snapData.ImageUUID
rbdSnap.RbdSnapName = snapData.ImageAttributes.ImageName
// it should never happen that this disagrees, but check
if rbdSnap.Pool != snapData.ImagePool {
return false, fmt.Errorf("stored snapshot pool (%s) and expected snapshot pool (%s) mismatch",
snapData.ImagePool, rbdSnap.Pool)
}
vol := generateVolFromSnap(rbdSnap)
defer vol.Destroy()
err = vol.Connect(cr)
if err != nil {
return false, err
}
vol.ReservedID = snapUUID
// Fetch on-disk image attributes
err = vol.getImageInfo()
if err != nil {
if _, ok := err.(ErrImageNotFound); ok {
err = parentVol.deleteSnapshot(ctx, rbdSnap)
if err != nil {
if _, ok := err.(ErrSnapNotFound); !ok {
klog.Errorf(util.Log(ctx, "failed to delete snapshot %s: %v"), rbdSnap, err)
return false, err
}
}
err = undoSnapshotCloning(ctx, vol, rbdSnap, vol, cr)
}
return false, err
}
// Snapshot creation transaction is rolled forward if rbd clone image
// representing the snapshot is found. Any failures till finding the image
// causes a roll back of the snapshot creation transaction.
// Code from here on, rolls the transaction forward.
rbdSnap.CreatedAt = vol.CreatedAt
rbdSnap.SizeBytes = vol.VolSize
// found a snapshot already available, process and return its information
rbdSnap.SnapID, err = util.GenerateVolID(ctx, rbdSnap.Monitors, cr, snapData.ImagePoolID, rbdSnap.Pool,
rbdSnap.ClusterID, snapUUID, volIDVersion)
if err != nil {
return false, err
}
// check snapshot exists if not create it
_, err = vol.getSnapInfo(rbdSnap)
if _, ok := err.(ErrSnapNotFound); ok {
// create snapshot
sErr := vol.createSnapshot(ctx, rbdSnap)
if sErr != nil {
klog.Errorf(util.Log(ctx, "failed to create snapshot %s: %v"), rbdSnap, sErr)
err = undoSnapshotCloning(ctx, vol, rbdSnap, vol, cr)
return false, err
}
}
if err != nil {
return false, err
}
vol.ImageID, err = j.GetStoredImageID(ctx, vol.JournalPool, vol.ReservedID, cr)
if _, ok := err.(util.ErrKeyNotFound); ok {
sErr := vol.getImageID()
if sErr != nil {
klog.Errorf(util.Log(ctx, "failed to get image id %s: %v"), vol, sErr)
err = undoSnapshotCloning(ctx, vol, rbdSnap, vol, cr)
return false, err
}
sErr = j.StoreImageID(ctx, vol.JournalPool, vol.ReservedID, vol.ImageID, cr)
if sErr != nil {
klog.Errorf(util.Log(ctx, "failed to store volume id %s: %v"), vol, sErr)
err = undoSnapshotCloning(ctx, vol, rbdSnap, vol, cr)
return false, err
}
}
if err != nil {
return false, err
}
klog.V(4).Infof(util.Log(ctx, "found existing image (%s) with name (%s) for request (%s)"),
rbdSnap.SnapID, rbdSnap.RbdSnapName, rbdSnap.RequestName)
return true, nil
}
/*
Check comment on checkSnapExists, to understand how this function behaves
**NOTE:** These functions manipulate the rados omaps that hold information regarding
volume names as requested by the CSI drivers. Hence, these need to be invoked only when the
respective CSI snapshot or volume name based locks are held, as otherwise racy access to these
omaps may end up leaving the omaps in an inconsistent state.
*/
func (rv *rbdVolume) Exists(ctx context.Context) (bool, error) {
err := validateRbdVol(rv)
if err != nil {
return false, err
}
kmsID := ""
if rv.Encrypted {
kmsID = rv.KMS.GetID()
}
j, err := volJournal.Connect(rv.Monitors, rv.conn.Creds)
if err != nil {
return false, err
}
defer j.Destroy()
imageData, err := j.CheckReservation(
ctx, rv.JournalPool, rv.RequestName, rv.NamePrefix, "", kmsID)
if err != nil {
return false, err
}
if imageData == nil {
return false, nil
}
rv.ReservedID = imageData.ImageUUID
rv.RbdImageName = imageData.ImageAttributes.ImageName
// check if topology constraints match what is found
rv.Topology, err = util.MatchTopologyForPool(rv.TopologyPools, rv.TopologyRequirement,
imageData.ImagePool)
if err != nil {
// TODO check if need any undo operation here, or ErrVolNameConflict
return false, err
}
// update Pool, if it was topology constrained
if rv.Topology != nil {
rv.Pool = imageData.ImagePool
}
// NOTE: Return volsize should be on-disk volsize, not request vol size, so
// save it for size checks before fetching image data
requestSize := rv.VolSize
// Fetch on-disk image attributes and compare against request
err = rv.getImageInfo()
if err != nil {
if _, ok := err.(ErrImageNotFound); ok {
err = j.UndoReservation(ctx, rv.JournalPool, rv.Pool,
rv.RbdImageName, rv.RequestName)
return false, err
}
return false, err
}
// size checks
if rv.VolSize < requestSize {
err = fmt.Errorf("image with the same name (%s) but with different size already exists",
rv.RbdImageName)
return false, ErrVolNameConflict{rv.RbdImageName, err}
}
// TODO: We should also ensure image features and format is the same
// found a volume already available, process and return it!
rv.VolID, err = util.GenerateVolID(ctx, rv.Monitors, rv.conn.Creds, imageData.ImagePoolID, rv.Pool,
rv.ClusterID, rv.ReservedID, volIDVersion)
if err != nil {
return false, err
}
klog.V(4).Infof(util.Log(ctx, "found existing volume (%s) with image name (%s) for request (%s)"),
rv.VolID, rv.RbdImageName, rv.RequestName)
return true, nil
}
// reserveSnap is a helper routine to request a rbdSnapshot name reservation and generate the
// volume ID for the generated name
func reserveSnap(ctx context.Context, rbdSnap *rbdSnapshot, rbdVol *rbdVolume, cr *util.Credentials) error {
var (
err error
)
journalPoolID, imagePoolID, err := util.GetPoolIDs(ctx, rbdSnap.Monitors, rbdSnap.JournalPool, rbdSnap.Pool, cr)
if err != nil {
return err
}
j, err := snapJournal.Connect(rbdSnap.Monitors, cr)
if err != nil {
return err
}
defer j.Destroy()
rbdSnap.ReservedID, rbdSnap.RbdSnapName, err = j.ReserveName(
ctx, rbdSnap.JournalPool, journalPoolID, rbdSnap.Pool, imagePoolID,
rbdSnap.RequestName, rbdSnap.NamePrefix, rbdVol.RbdImageName, "")
if err != nil {
return err
}
rbdSnap.SnapID, err = util.GenerateVolID(ctx, rbdSnap.Monitors, cr, imagePoolID, rbdSnap.Pool,
rbdSnap.ClusterID, rbdSnap.ReservedID, volIDVersion)
if err != nil {
return err
}
klog.V(4).Infof(util.Log(ctx, "generated Volume ID (%s) and image name (%s) for request name (%s)"),
rbdSnap.SnapID, rbdSnap.RbdSnapName, rbdSnap.RequestName)
return nil
}
func updateTopologyConstraints(rbdVol *rbdVolume, rbdSnap *rbdSnapshot) error {
var err error
if rbdSnap != nil {
// check if topology constraints matches snapshot pool
rbdVol.Topology, err = util.MatchTopologyForPool(rbdVol.TopologyPools,
rbdVol.TopologyRequirement, rbdSnap.Pool)
if err != nil {
return err
}
// update Pool, if it was topology constrained
if rbdVol.Topology != nil {
rbdVol.Pool = rbdSnap.Pool
}
return nil
}
// update request based on topology constrained parameters (if present)
poolName, dataPoolName, topology, err := util.FindPoolAndTopology(rbdVol.TopologyPools, rbdVol.TopologyRequirement)
if err != nil {
return err
}
if poolName != "" {
rbdVol.Pool = poolName
rbdVol.DataPool = dataPoolName
rbdVol.Topology = topology
}
return nil
}
// reserveVol is a helper routine to request a rbdVolume name reservation and generate the
// volume ID for the generated name
func reserveVol(ctx context.Context, rbdVol *rbdVolume, rbdSnap *rbdSnapshot, cr *util.Credentials) error {
var (
err error
)
err = updateTopologyConstraints(rbdVol, rbdSnap)
if err != nil {
return err
}
journalPoolID, imagePoolID, err := util.GetPoolIDs(ctx, rbdVol.Monitors, rbdVol.JournalPool, rbdVol.Pool, cr)
if err != nil {
return err
}
kmsID := ""
if rbdVol.Encrypted {
kmsID = rbdVol.KMS.GetID()
}
j, err := volJournal.Connect(rbdVol.Monitors, cr)
if err != nil {
return err
}
defer j.Destroy()
rbdVol.ReservedID, rbdVol.RbdImageName, err = j.ReserveName(
ctx, rbdVol.JournalPool, journalPoolID, rbdVol.Pool, imagePoolID,
rbdVol.RequestName, rbdVol.NamePrefix, "", kmsID)
if err != nil {
return err
}
rbdVol.VolID, err = util.GenerateVolID(ctx, rbdVol.Monitors, cr, imagePoolID, rbdVol.Pool,
rbdVol.ClusterID, rbdVol.ReservedID, volIDVersion)
if err != nil {
return err
}
klog.V(4).Infof(util.Log(ctx, "generated Volume ID (%s) and image name (%s) for request name (%s)"),
rbdVol.VolID, rbdVol.RbdImageName, rbdVol.RequestName)
return nil
}
// undoSnapReservation is a helper routine to undo a name reservation for rbdSnapshot
func undoSnapReservation(ctx context.Context, rbdSnap *rbdSnapshot, cr *util.Credentials) error {
j, err := snapJournal.Connect(rbdSnap.Monitors, cr)
if err != nil {
return err
}
defer j.Destroy()
err = j.UndoReservation(
ctx, rbdSnap.JournalPool, rbdSnap.Pool, rbdSnap.RbdSnapName,
rbdSnap.RequestName)
return err
}
// undoVolReservation is a helper routine to undo a name reservation for rbdVolume
func undoVolReservation(ctx context.Context, rbdVol *rbdVolume, cr *util.Credentials) error {
j, err := volJournal.Connect(rbdVol.Monitors, cr)
if err != nil {
return err
}
defer j.Destroy()
err = j.UndoReservation(ctx, rbdVol.JournalPool, rbdVol.Pool,
rbdVol.RbdImageName, rbdVol.RequestName)
return err
}