rohitg00/k8s-autoscaling

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:

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:

kubectl_apply(hpa_yaml, namespace)
get_hpa(namespace)

VPA (Vertical Pod Autoscaler)

Right-size resource requests:

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

keda_detect_tool()

List ScaledObjects

keda_scaledobjects_list_tool(namespace)
keda_scaledobject_get_tool(name, namespace)

List ScaledJobs

keda_scaledjobs_list_tool(namespace)

Trigger Authentication

keda_triggerauths_list_tool(namespace)
keda_triggerauth_get_tool(name, namespace)

KEDA-Managed HPAs

keda_hpa_list_tool(namespace)

See KEDA-TRIGGERS.md for trigger configurations.

Common KEDA Triggers

Queue-Based Scaling (AWS SQS)

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

triggers:
- type: cron
  metadata:
    timezone: America/New_York
    start: 0 8 * * 1-5
    end: 0 18 * * 1-5
    desiredReplicas: "10"

Prometheus Metrics

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:

keda_scaledobjects_list_tool(namespace)

Right-Size with VPA

Get recommendations and apply:

get_resource_recommendations(namespace)

Troubleshooting

HPA Not Scaling

get_hpa(namespace)
get_pod_metrics(name, namespace)
describe_pod(name, namespace)

KEDA Not Triggering

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 - Cost optimization
• k8s-troubleshoot - Debug scaling issues