---
name: k8s-autoscaling
description: Configure Kubernetes autoscaling with HPA, VPA, and KEDA. Use for horizontal/vertical pod autoscaling, event-driven scaling, and capacity management.
license: Apache-2.0
metadata:
author: rohitg00
version: "1.0.0"
tools: 7
category: scaling
---
# Kubernetes Autoscaling
Comprehensive autoscaling using HPA, VPA, and KEDA with kubectl-mcp-server tools.
## When to Apply
Use this skill when:
- User mentions: "HPA", "VPA", "KEDA", "autoscale", "scale to zero"
- Operations: configuring autoscaling, checking scaling status
- Keywords: "scale automatically", "event-driven", "right-size"
## Priority Rules
| Priority | Rule | Impact | Tools |
|----------|------|--------|-------|
| 1 | Verify metrics-server for HPA | CRITICAL | `get_resource_metrics` |
| 2 | Set resource requests before HPA | CRITICAL | `describe_pod` |
| 3 | Use KEDA for scale-to-zero | HIGH | `keda_scaledobjects_list_tool` |
| 4 | Check VPA recommendations | MEDIUM | `get_resource_recommendations` |
## Quick Reference
| Task | Tool | Example |
|------|------|---------|
| List KEDA ScaledObjects | `keda_scaledobjects_list_tool` | `keda_scaledobjects_list_tool(namespace)` |
| Get ScaledObject | `keda_scaledobject_get_tool` | `keda_scaledobject_get_tool(name, namespace)` |
| List ScaledJobs | `keda_scaledjobs_list_tool` | `keda_scaledjobs_list_tool(namespace)` |
| Check KEDA | `keda_detect_tool` | `keda_detect_tool()` |
## HPA (Horizontal Pod Autoscaler)
Basic CPU-based scaling:
```yaml
apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
name: my-app-hpa
spec:
scaleTargetRef:
apiVersion: apps/v1
kind: Deployment
name: my-app
minReplicas: 2
maxReplicas: 10
metrics:
- type: Resource
resource:
name: cpu
target:
type: Utilization
averageUtilization: 70
```
Apply and verify:
```python
kubectl_apply(hpa_yaml, namespace)
get_hpa(namespace)
```
## VPA (Vertical Pod Autoscaler)
Right-size resource requests:
```yaml
apiVersion: autoscaling.k8s.io/v1
kind: VerticalPodAutoscaler
metadata:
name: my-app-vpa
spec:
targetRef:
apiVersion: apps/v1
kind: Deployment
name: my-app
updatePolicy:
updateMode: "Auto"
```
## KEDA (Event-Driven Autoscaling)
### Detect KEDA Installation
```python
keda_detect_tool()
```
### List ScaledObjects
```python
keda_scaledobjects_list_tool(namespace)
keda_scaledobject_get_tool(name, namespace)
```
### List ScaledJobs
```python
keda_scaledjobs_list_tool(namespace)
```
### Trigger Authentication
```python
keda_triggerauths_list_tool(namespace)
keda_triggerauth_get_tool(name, namespace)
```
### KEDA-Managed HPAs
```python
keda_hpa_list_tool(namespace)
```
See [KEDA-TRIGGERS.md](KEDA-TRIGGERS.md) for trigger configurations.
## Common KEDA Triggers
### Queue-Based Scaling (AWS SQS)
```yaml
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
name: sqs-scaler
spec:
scaleTargetRef:
name: queue-processor
minReplicaCount: 0
maxReplicaCount: 100
triggers:
- type: aws-sqs-queue
metadata:
queueURL: https://sqs.region.amazonaws.com/...
queueLength: "5"
```
### Cron-Based Scaling
```yaml
triggers:
- type: cron
metadata:
timezone: America/New_York
start: 0 8 * * 1-5
end: 0 18 * * 1-5
desiredReplicas: "10"
```
### Prometheus Metrics
```yaml
triggers:
- type: prometheus
metadata:
serverAddress: http://prometheus:9090
metricName: http_requests_total
query: sum(rate(http_requests_total{app="myapp"}[2m]))
threshold: "100"
```
## Scaling Strategies
| Strategy | Tool | Use Case |
|----------|------|----------|
| CPU/Memory | HPA | Steady traffic patterns |
| Custom metrics | HPA v2 | Business metrics |
| Event-driven | KEDA | Queue processing, cron |
| Vertical | VPA | Right-size requests |
| Scale to zero | KEDA | Cost savings, idle workloads |
## Cost-Optimized Autoscaling
### Scale to Zero with KEDA
Reduce costs for idle workloads:
```python
keda_scaledobjects_list_tool(namespace)
```
### Right-Size with VPA
Get recommendations and apply:
```python
get_resource_recommendations(namespace)
```
## Troubleshooting
### HPA Not Scaling
```python
get_hpa(namespace)
get_pod_metrics(name, namespace)
describe_pod(name, namespace)
```
### KEDA Not Triggering
```python
keda_scaledobject_get_tool(name, namespace)
get_events(namespace)
```
### Common Issues
| Symptom | Check | Resolution |
|---------|-------|------------|
| HPA unknown | Metrics server | Install metrics-server |
| KEDA no scale | Trigger auth | Check TriggerAuthentication |
| VPA not updating | Update mode | Set updateMode: Auto |
| Scale down slow | Stabilization | Adjust stabilizationWindowSeconds |
## Best Practices
1. **Always Set Resource Requests** - HPA requires requests to calculate utilization
2. **Use Multiple Metrics** - Combine CPU + custom metrics for accuracy
3. **Stabilization Windows** - Prevent flapping with scaleDown stabilization
4. **Scale to Zero Carefully** - Consider cold start time
## Related Skills
- [k8s-cost](../k8s-cost/SKILL.md) - Cost optimization
- [k8s-troubleshoot](../k8s-troubleshoot/SKILL.md) - Debug scaling issues
