What is Kubernetes Vertical Pod Autoscaler (VPA)?

Question

Accepted Answer

**VPA** — automatically adjusts Pod resource requests/limits.

```yaml
apiVersion: autoscaling.k8s.io/v1
kind: VerticalPodAutoscaler
metadata:
  name: myapp-vpa
spec:
  targetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: myapp
  updatePolicy:
    updateMode: "Off"  # Recommendations only
  resourcePolicy:
    containerPolicies:
    - containerName: app
      minAllowed:
        cpu: "100m"
        memory: "128Mi"
      maxAllowed:
        cpu: "4"
        memory: "4Gi"
      controlledResources: ["cpu", "memory"]
      controlledValues: RequestsAndLimits
    - containerName: sidecar
      mode: "Off"  # Don't touch this container
---
# Auto mode (recommended for non-critical)
apiVersion: autoscaling.k8s.io/v1
kind: VerticalPodAutoscaler
metadata:
  name: myapp-vpa-auto
spec:
  targetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: myapp
  updatePolicy:
    updateMode: "Auto"
    minReplicas: 2
```

```bash
# Install VPA
kubectl apply -f vpa-crd.yaml
kubectl get vpa
kubectl describe vpa myapp-vpa

# Check recommendations
kubectl get vpa myapp-vpa -o yaml | grep -A 10 recommendations
```

**Update Modes:**
- Off: recommendations only.
- Initial: set on Pod creation.
- Recreate: restart Pods with new resources.
- Auto: auto-select between Initial/Recreate.

**vs HPA:**
- HPA: scale count.
- VPA: adjust resources per Pod.

DevOps: What is Kubernetes Vertical Pod Autoscaler (VPA)?