docs: add migration guide from in-tree to plugin-based Barman Cloud (#316)

This commit introduces documentation that guides users through the process of
migrating an existing CloudNativePG cluster from the built-in (in-tree) Barman
Cloud integration to the external Barman Cloud Plugin.

Closes #312.

Signed-off-by: Gabriele Bartolini <gabriele.bartolini@enterprisedb.com>
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@ -41,6 +41,10 @@ WAL files are archived in the `wals` directory, while base backups are stored
as **tarballs** in the `base` directory, following the
[Barman Cloud convention](https://docs.pgbarman.org/cloud/latest/usage/#object-store-layout).
The plugin also offers advanced capabilities, including
[backup tagging](misc.md#backup-object-tagging) and
[extra options for backups and WAL archiving](misc.md#extra-options-for-backup-and-wal-archiving).
:::tip
For details, refer to the
[API reference for the `ObjectStore` resource](plugin-barman-cloud.v1.md#objectstorespec).

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@ -12,6 +12,13 @@ enables online continuous physical backups of PostgreSQL clusters to object stor
using the `barman-cloud` suite from the [Barman](https://docs.pgbarman.org/release/latest/)
project.
:::important
If you plan to migrate your existing CloudNativePG cluster to the new
plugin-based approach using the Barman Cloud Plugin, see
["Migrating from Built-in CloudNativePG Backup"](migration.md)
for detailed instructions.
:::
## Requirements
To use the Barman Cloud Plugin, you need:

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@ -2,8 +2,175 @@
sidebar_position: 40
---
# Migrating from CloudNativePG
# Migrating from Built-in CloudNativePG Backup
<!-- SPDX-License-Identifier: CC-BY-4.0 -->
TODO
The in-tree support for Barman Cloud in CloudNativePG is **deprecated starting
from version 1.26** and will be removed in a future release.
If you're currently relying on the built-in Barman Cloud integration, you can
migrate seamlessly to the new **plugin-based architecture** using the Barman
Cloud Plugin, with **no downtime**. Follow these steps:
- [Install the Barman Cloud Plugin](installation.md)
- Create an `ObjectStore` resource by translating the contents of the
`.spec.backup.barmanObjectStore` section from your existing `Cluster`
definition
- Modify the `Cluster` resource in a single atomic change to switch from
in-tree backup to the plugin
- Update any `ScheduledBackup` resources to use the plugin
:::tip
For a working example, refer to [this commit](https://github.com/cloudnative-pg/cnpg-playground/commit/596f30e252896edf8f734991c3538df87630f6f7)
from the [CloudNativePG Playground project](https://github.com/cloudnative-pg/cnpg-playground),
which demonstrates a full migration.
:::
---
## Step 1: Define the `ObjectStore`
Begin by creating an `ObjectStore` resource in the same namespace as your
PostgreSQL `Cluster`.
There is a **direct mapping** between the `.spec.backup.barmanObjectStore`
section in CloudNativePG and the `.spec.configuration` field in the
`ObjectStore` CR. The conversion is mostly mechanical, with one key difference:
:::warning
In the plugin architecture, retention policies are defined as part of the `ObjectStore`.
In contrast, the in-tree implementation defined them at the `Cluster` level.
:::
If your `Cluster` used `.spec.backup.retentionPolicy`, move that configuration
to `.spec.retentionPolicy` in the `ObjectStore`.
---
### Example
Heres an excerpt from a traditional in-tree CloudNativePG backup configuration
taken from the CloudNativePG Playground project:
```yaml
apiVersion: postgresql.cnpg.io/v1
kind: Cluster
metadata:
name: pg-eu
spec:
# [...]
backup:
barmanObjectStore:
destinationPath: s3://backups/
endpointURL: http://minio-eu:9000
s3Credentials:
accessKeyId:
name: minio-eu
key: ACCESS_KEY_ID
secretAccessKey:
name: minio-eu
key: ACCESS_SECRET_KEY
wal:
compression: gzip
```
This configuration translates to the following `ObjectStore` resource for the
plugin:
```yaml
apiVersion: barmancloud.cnpg.io/v1
kind: ObjectStore
metadata:
name: minio-eu
spec:
configuration:
destinationPath: s3://backups/
endpointURL: http://minio-eu:9000
s3Credentials:
accessKeyId:
name: minio-eu
key: ACCESS_KEY_ID
secretAccessKey:
name: minio-eu
key: ACCESS_SECRET_KEY
wal:
compression: gzip
```
As you can see, the contents of `barmanObjectStore` have been copied directly
under the `configuration` field of the `ObjectStore` resource, using the same
secret references.
## Step 2: Update the `Cluster`
Once the `ObjectStore` resource is in place, update the `Cluster` resource as
follows in a single atomic change:
- Remove the `.spec.backup.barmanObjectStore` section
- Remove `.spec.backup.retentionPolicy` if it was defined (as it is now in the
`ObjectStore`)
- Remove the entire `spec.backup` section if it is now empty
- Add `barman-cloud.cloudnative-pg.io` to the `plugins` list, as described in
[Configuring WAL archiving](usage.md#configuring-wal-archiving)
This will trigger a rolling update of the `Cluster`, switching continuous
backup from the in-tree implementation to the plugin-based approach.
### Example
The updated `pg-eu` cluster will have this configuration instead of the
previous `backup` section:
```yaml
plugins:
- name: barman-cloud.cloudnative-pg.io
isWALArchiver: true
parameters:
barmanObjectName: minio-eu
```
---
## Step 3: Update the `ScheduledBackup`
After switching the `Cluster` to use the plugin, update your `ScheduledBackup`
resources to match.
Set the backup `method` to `plugin` and reference the plugin name via
`pluginConfiguration`, as shown in ["Performing a base backup"](usage.md#performing-a-base-backup).
### Example
Original in-tree `ScheduledBackup`:
```yaml
apiVersion: postgresql.cnpg.io/v1
kind: ScheduledBackup
metadata:
name: pg-eu-backup
spec:
cluster:
name: pg-eu
schedule: '0 0 0 * * *'
backupOwnerReference: self
```
Updated version using the plugin:
```yaml
apiVersion: postgresql.cnpg.io/v1
kind: ScheduledBackup
metadata:
name: pg-eu-backup
spec:
cluster:
name: pg-eu
schedule: '0 0 0 * * *'
backupOwnerReference: self
method: plugin
pluginConfiguration:
name: barman-cloud.cloudnative-pg.io
```
---