Update statefulset.md

feat: add `controllerrevision` to StatefulSet

Author: husnialhamdani

content/en/docs/concepts/workloads/controllers/statefulset.md

@@ -383,6 +383,99 @@ After reverting the template, you must also delete any Pods that StatefulSet had
 already attempted to run with the bad configuration.
 StatefulSet will then begin to recreate the Pods using the reverted template.
 
+## Revision History and ControllerRevisions
+
+**ControllerRevisions** are Kubernetes objects used by controllers like StatefulSets to track historical configuration changes. StatefulSets use ControllerRevisions to maintain a revision history, enabling rollbacks and version tracking.
+
+---
+
+### How ControllerRevisions Work with StatefulSets
+
+When you update a StatefulSet's Pod template (`spec.template`), the StatefulSet controller:
+
+1. Creates a new ControllerRevision object  
+2. Stores a snapshot of the Pod template and metadata  
+3. Assigns an incremental revision number  
+
+#### Key Properties
+
+- **Name Format**: `<statefulset-name>-<revision-number>` (e.g., `webapp-2`)
+- **Stored Data**:
+  - Complete Pod template configuration at time of update
+  - Revision number (monotonically increasing integer)
+  - Owner reference to the parent StatefulSet
+- **Retention**: Automatically deleted when parent StatefulSet is removed
+
+---
+
+### Managing Revision History
+
+Control retained revisions with `.spec.revisionHistoryLimit`:
+
+```yaml
+apiVersion: apps/v1
+kind: StatefulSet
+metadata:
+  name: webapp
+spec:
+  revisionHistoryLimit: 5  # Keep last 5 revisions
+  # ... other spec fields ...
+```
+
+- **Default**: 10 revisions retained if unspecified  
+- **Cleanup**: Oldest revisions are garbage-collected when exceeding the limit
+
+#### Performing Rollbacks
+
+You can revert to a previous configuration using:
+
+```bash
+# View revision history
+kubectl rollout history statefulset/webapp
+
+# Rollback to a specific revision
+kubectl rollout undo statefulset/webapp --to-revision=3
+```
+
+This will:
+
+- Apply the Pod template from revision 3  
+- Create a new ControllerRevision with an updated revision number  
+
+#### Inspecting ControllerRevisions
+
+To view associated ControllerRevisions:
+
+```bash
+# List all revisions for the StatefulSet
+kubectl get controllerrevisions -l app.kubernetes.io/name=webapp
+
+# View detailed configuration of a specific revision
+kubectl get controllerrevision/webapp-3 -o yaml
+```
+
+#### Best Practices
+
+##### Retention Policy
+
+- Set `revisionHistoryLimit` between **5–10** for most workloads  
+- Increase only if **deep rollback history** is required  
+
+##### Monitoring
+
+- Regularly check revisions with:
+
+  ```bash
+  kubectl get controllerrevisions
+  ```
+
+- Alert on **rapid revision count growth**
+
+##### Avoid
+
+- Manual edits to ControllerRevision objects  
+- Using revisions as a backup mechanism (use actual backup tools)  
+- Setting `revisionHistoryLimit: 0` (disables rollback capability)
 
 ## PersistentVolumeClaim retention