Enable snapshots for all backups

This tutorial shows three ways to enable snapshots on every Backup, instead of annotating each Backup by hand.

With snapshots enabled, a Backup detects when a topic is deleted and recreated, archives the existing backup data as a numbered snapshot, and continues backing up the new topic without manual intervention.

Prerequisites

A Kannika Armory instance available, running on a Kubernetes environment.
Local installation of the kubectl binary.
A Kafka cluster that supports topic UUIDs (KIP-516).

Snapshots only apply to topics that do not have any backup data yet. Topics that were already backed up keep using the original layout, even after the annotation is added. See Compatibility with existing backups for details.

Choose an approach

Approach	Existing Backups	New Backups	Best for
kubectl	Yes	No	A one-off change on a cluster
Kustomize	Yes	Yes	Backups managed as manifests in Git
Kyverno	No	Yes	Backups created from the console or API

Option A: kubectl

Annotate every Backup in every namespace:

kubectl annotate backups.kannika.io --all --all-namespaces \
  io.kannika/experimental-snapshots=true

A Backup that already has the annotation is left unchanged, and kubectl reports an error for it. Add --overwrite to also set the annotation on those Backups, for example to turn snapshots on for a Backup where they were explicitly turned off.

The operator redeploys each annotated Backup with snapshots enabled.

This only changes the Backups that exist when you run the command. Backups that are created later do not get the annotation.

Option B: Kustomize

If your Backups are managed as manifests, add the annotation with a Kustomize patch that targets every Backup.

Given a backups/ directory that holds the Backup manifests, create a kustomization.yaml next to it:

resources:
  - backups/

patches:
  - target:
      group: kannika.io
      kind: Backup
    patch: |-
      apiVersion: kannika.io/v1alpha
      kind: Backup
      metadata:
        name: ignored
        annotations:
          io.kannika/experimental-snapshots: "true"

The target selects every Backup, so the name in the patch is ignored.

Preview the result:

kubectl kustomize .

Apply it:

kubectl apply -k .

Every Backup that is added to the backups/ directory later gets the annotation as well.

Option C: Kyverno

Backups that are created from the console or the API are not part of your manifests. A Kyverno mutate policy adds the annotation to every Backup when it is created or updated, no matter where it comes from.

This option requires Kyverno to be installed on the cluster.

Create a file named kannika-enable-snapshots.clusterpolicy.yaml:

apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
  name: kannika-enable-snapshots
spec:
  rules:
    - name: add-experimental-snapshots
      match:
        any:
          - resources:
              kinds:
                - kannika.io/v1alpha/Backup
      mutate:
        patchStrategicMerge:
          metadata:
            annotations:
              +(io.kannika/experimental-snapshots): "true"

The +(...) anchor only adds the annotation when it is not set yet, so a Backup where snapshots are explicitly turned off with "false" keeps that value.

Apply the policy:

kubectl apply -f kannika-enable-snapshots.clusterpolicy.yaml

The policy only mutates Backups when they are created or updated. To enable snapshots on the Backups that already exist, run the command from Option A once.

Verify the result

List the Backups with the value of the annotation:

kubectl get backups.kannika.io --all-namespaces \
  -o custom-columns='NAMESPACE:.metadata.namespace,NAME:.metadata.name,SNAPSHOTS:.metadata.annotations.io\.kannika/experimental-snapshots'

NAMESPACE      NAME            SNAPSHOTS
kannika-data   orders-backup   true
kannika-data   users-backup    true

A Backup without the annotation shows <none>.

Summary

In this tutorial, you learned how to enable snapshots on every Backup:

With kubectl annotate, for the Backups that exist today
With a Kustomize patch, for Backups that are managed as manifests
With a Kyverno policy, for every Backup that is created or updated from now on

See Snapshots to restore from a specific snapshot version, or to list the snapshots of a topic.