DevOps: What is Kubernetes Horizontal Pod Autoscaler (HPA)?

1apiVersion: autoscaling/v2
2kind: HorizontalPodAutoscaler
3metadata:
4  name: myapp-hpa
5spec:
6  scaleTargetRef:
7    apiVersion: apps/v1
8    kind: Deployment
9    name: myapp
10  minReplicas: 2
11  maxReplicas: 20
12  metrics:
13  - type: Resource
14    resource:
15      name: cpu
16      target:
17        type: Utilization
18        averageUtilization: 70
19  - type: Resource
20    resource:
21      name: memory
22      target:
23        type: Utilization
24        averageUtilization: 80
25  - type: Pods
26    pods:
27      metric:
28        name: http_requests_per_second
29      target:
30        type: AverageValue
31        averageValue: "1000"
32  - type: External
33    external:
34      metric:
35        name: sqs_queue_length
36      target:
37        type: Value
38        value: "30"
39  behavior:
40    scaleUp:
41      stabilizationWindowSeconds: 60
42      policies:
43      - type: Percent
44        value: 100
45        periodSeconds: 60
46    scaleDown:
47      stabilizationWindowSeconds: 300
48      policies:
49      - type: Percent
50        value: 10
51        periodSeconds: 60

1# Commands
2kubectl get hpa
3kubectl describe hpa myapp-hpa
4kubectl autoscale deployment myapp --min=2 --max=10 --cpu-percent=70
5kubectl top pods  # Check current metrics