feat(lep): multiple backup stores support

Ref: 5411 Signed-off-by: James Lu <james.lu@suse.com>
longhorn · Sep 5, 2023 · b43e811 · b43e811
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+# Multiple Backup Stores Support
+
+## Summary
+
+The current Longhorn only support a single backup store for all volumes. The feature aims to provide multiple backup stores with tiering.
+
+### Related Issues
+
+https://github.com/longhorn/longhorn/issues/2317
+https://github.com/longhorn/longhorn/issues/5411
+
+## Motivation
+
+Users can choose backup stores to that they want to back up volumes.
+
+### Goals
+
+- There are difference backup targets at the same time on Longhorn.
+- Backups can be synchronized from difference remote backup targets.
+- Backups can be backed up to difference remote backup targets.
+- A backup can be restored from difference remote backup targets to be a new volume.
+
+### Non-goals [optional]
+
+`None`
+
+## Proposal
+
+1. Allow users to create, delete or modify extra backup targets except `default`.
+     - backup target controller needs to synchronize the data from the extra backup target created.
+     - backup target controller needs to delete the data in the cluster related the extra backup target deleted.
+2. Introduce new fields `BackupTargetURL` in `Spec` and `BackupTargetName` in `Status` of both BackupVolume and Backup CRDs to keep backup target information.
+
+### User Stories
+
+User can setup the default backup target as usual on the page `Setting/General` and create extra backup targets on the page `Settings/Backup Target` or create/modify backup targets by the manifest. After extra backup targets created and synchronized, users can start to create a backup on these remote backup targets.
+
+### User Experience In Detail
+
+#### Create Or Modify Backup Targets By UI
+
+1. User can find the link `Backup Target` in drop down menu of `Setting`.
+2. We have a default backup target on the page `Backup Target` and it would show its name, backup target url, secret name for this backup target (credential), poll interval and availability status.
+3. User can create a new backup target on the page `Backup Target` by clicking the button `Create`.
+4. User have to fill out the necessary items for backup target name and url, and secret(credential) name, poll interval can be optional.
+5. User can click the button `Edit` to modify the backup target information.
+
+#### Create Or Modify Backup Targets By CLI
+
+User can the bash command to create or modify a backup target such as below:
+
+```bash
+cat <<EOF >>new-backup-target.yaml
+apiVersion: longhorn.io/v1beta2
+kind: BackupTarget
+metadata:
+  name: azure-blob-server-001
+  namespace: longhorn-system
+spec:
+  backupTargetURL: azblob://demo@core.windows.net/
+  credentialSecret: azblob-secret
+  pollInterval: 4m30s
+status:
+  default: true
+EOF
+
+kubectl apply -f new-backup-target.yaml
+```
+
+#### Create A Backup To Remote Backup Targets By UI
+
+After users click the button `Create Backup` on the `Volume Details` page, they can choose multiple backup targets they just created by checkboxes to create backups on backup targets.
+
+#### Create A Backup To Remote Backup Targets By CLI
+
+1. Create a snapshot of the volume first
+2. Create backups for each backup target you want to store the snapshot by the manifest as below:
+
+```txt
+apiVersion: longhorn.io/v1beta2
+kind: Backup
+metadata:
+  labels:
+    backup-volume: pvc-xxxxxxxx-9ab9-4055-9eb4-558999b09a11
+  name: backup-test-001
+  namespace: longhorn-system
+spec:
+  backupTarget: azure-blob-server-001
+  labels:
+    longhorn.io/volume-access-mode: rwo
+  snapshotName: xxxxxxxx-9a69-4ede-ab88-c9853459462c
+status:
+  default: true
+```
+
+#### Restore From A Backup From A Remote Backup Target
+
+Restoring from a backup will behave as before. Choose a backup and do the `Restore` operation in drop down menu on UI.
+
+### API changes
+
+- Introduce new APIs `BackupTargetCreate`,`BackupTargetDelete` and `BackupTargetGet`:
+
+    | API | Input | Output | Comments | HTTP Endpoint |
+    | --- | --- | --- | --- | --- |
+    | Create | name, backupTargetURL, credentialSecret string, pollInterval time.Duration, default boolean | err error | Create a new backup target and start to synchronize data | **POST** `/v1/backuptargets/{backupTargetName}` |
+    | Delete | name string | err error | Remove a backup target and its related backup volume and backup CR objects in the cluster | **DELETE** `/v1/backuptargets/{backupTargetName}` |
+    | Get    |  | backupTarget BackupTarget, err error | Get the backup targets information | **GET** `/v1/backuptargets/{backupTargetName}` |
+    | Update | backupTargetURL, credentialSecret string, pollInterval time.Duration, default boolean | err error | Update the backup targets information | **PUT** `/v1/backuptargets/{backupTargetName}` |
+
+- Modify the APIs `BackupVolumeGet`, `BackupVolumeList`:
+  - Add new fields `BackupTargetName` and `VolumeName` in returning `BackupVolume` information.
+- Modify the APIs `BackupCreate`, `BackupGet`:
+  - Add a new field `BackupTargetName` in returning `Backup` information.
+
+## Design
+
+### Implementation Overview
+
+#### CRDs
+
+1. Modify the Backup CRD `backups.longhorn.io` to add new fields `BackupTargetURL` in `Spec` and `BackupTargetName` in `Status`.
+
+  ```yaml
+  metadata:
+    name: the backup name. (string)
+  spec:
+    backupTargetURL: the backup target URL. (string)
+  status:
+    backupTargetName: the backup target Name. (string)
+  ```
+
+2. Modify the Backup Volume CRD `backupvolumes.longhorn.io` to add new fields `BackupTargetURL` and `VolumeName` in `Spec` and `BackupTargetName` in `Status`.
+
+  ```yaml
+  metadata:
+    name: the backup name. (string)
+  spec:
+    backupTargetURL: the backup target URL. (string)
+    volumeName:  the volume name for backups. (string)
+  status:
+    backupTargetName: the backup target Name. (string)
+  ```
+
+3. Modify the Backup Target CRD `backuptagets.longhorn.io` to add a new fields `Default` in `Status`.
+
+  ```yaml
+  metadata:
+    name: the backup name. (string)
+  ...
+  status:
+    default: the backup target is default or not. (boolean)
+  ```
+
+#### Backup Related Controllers
+
+1. Remove `default` backup target from the setting controller.
+
+2. Modify backup target controller to allow to add and delete a extra backup target.
+
+   - Clean up backup volume CR objects in the cluster by label `backup-target` when deleting a backup target.
+   - Create a pulling backup volume from the backup target by the backup volume name `volumeName` + `-` + `backupTarget.Name` and adding a label `backup-target` with the backup target URL.
+   - Get backup volume CR objects in the cluster by label `backup-target` with the backup target URL.
+
+3. Modify backup volume controller to tell which backup volume belongs to which backup target and synchronize the backups of the backup volume from remote backup target.
+
+   - Clean up backup CR objects in the cluster by the volume name `backupVolume.Spec.volumeName` and `backupVolume.Spec.backupTargetURL` when deleting a backup volume.
+   - Create a pulling backup from the backup target by the volume name `backupVolume.Spec.volumeName` and `backupVolume.Spec.backupTargetURL`.
+
+### Test plan
+
+1. Setup the default backup target.
+2. Create a backup to default backup target and it succeeds.
+3. Setup an extra old backup target.
+4. Backups created with default backup target will not be deleted.
+5. Backups on the extra old backup target can be synchronized.
+6. Create a backup to extra backup target and it succeeds.
+7. Restore a backup from default remote backup target, and it succeeds and data is correct.
+8. Restore a backup from the extra remote backup target, and it succeeds and data is correct.
+
+### Upgrade strategy
+
+1. Fill in fields `BackupTargetURL` in `Spec` and `BackupTargetName` in `Status` for backup CR objects with corresponding values.
+2. Fill in fields `BackupTargetURL` and `VolumeName` in `Spec` and `BackupTargetName` in `Status` for backup volume CR objects with corresponding values.
+
+## Note [optional]
+
+`None`