Horizontal Pod Autoscaler

Auto-scale Deployments based on CPU utilization (1–3 replicas at 50% CPU)

📋Configuration Files

hpa.yml

HPA for two microservices — scales on CPU averageUtilization 50%

yaml

1apiVersion: autoscaling/v2
2kind: HorizontalPodAutoscaler
3metadata:
4  name: hpa-springapi-svc-a
5spec:
6  scaleTargetRef:
7    apiVersion: apps/v1
8    kind: Deployment
9    name: service-a
10  minReplicas: 1
11  maxReplicas: 3
12  metrics:
13    - type: Resource
14      resource:
15        name: cpu
16        target:
17          type: Utilization
18          averageUtilization: 50
19---
20apiVersion: autoscaling/v2
21kind: HorizontalPodAutoscaler
22metadata:
23  name: hpa-springapi-svc-b
24spec:
25  scaleTargetRef:
26    apiVersion: apps/v1
27    kind: Deployment
28    name: service-b
29  minReplicas: 1
30  maxReplicas: 3
31  metrics:
32    - type: Resource
33      resource:
34        name: cpu
35        target:
36          type: Utilization
37          averageUtilization: 50

📄

Step 01

Enable HPA

(01)Install metrics-server (required for CPU metrics)

Linux

1kubectl apply -f https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml
2kubectl get deployment metrics-server -n kube-system

(02)Apply HPA and monitor scaling

Linux

1kubectl apply -f hpa.yml
2kubectl get hpa
3kubectl describe hpa hpa-springapi-svc-a
4watch kubectl get pods