Kubernetes Horizontal Pod Autoscaler (HPA): Autoscale Your Application Workloads using Kubernetes

 

Kubernetes Horizontal Pod Autoscaler (HPA) Setup

Prerequisites:  metrics-server

For Minikube users: 

minikube addons enable metrics-server 

For kubernetes cluster:

kubectl apply -f https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml

1.  At first create the deployments.yaml

apiVersion: apps/v1

kind: Deployment

metadata:

name: web-servers

labels:

app: web-servers

spec:

selector:

matchLabels:

app: web-servers

replicas: 1

template:

metadata:

labels:

app: web-servers

spec:

containers:

- name: nginx

image: nginx

ports:

- containerPort: 80

resources:

limits:

cpu: 30m

memory: 50Mi

requests:

cpu: 10m

memory: 10Mi

2. Then create the service.yaml. Here, i am using NodePort

apiVersion: v1

kind: Service

metadata:

labels:

app: web-servers

name: web-servers

namespace: default

spec:

ports:

- name: web-servers-port

port: 80

selector:

app: web-servers

sessionAffinity: None

type: NodePort

3. Then finally create the Horizontal Pod Autoscaler in autoscaler.yaml. Here, I have definded 20%  threshold for CPU  usage and 30Mi threshold for Memory. Minimum replica is 1 and Maximum replica is 3. You can modifiy it according to your needs. That means the autoscaling will be triggered after the usage of this threshold values.

apiVersion: autoscaling/v2

kind: HorizontalPodAutoscaler

metadata:

name: web-servers

spec:

scaleTargetRef:

apiVersion: apps/v1

kind: Deployment

name: web-servers

minReplicas: 1

maxReplicas: 3

metrics:

- type: Resource

resource:

name: cpu

target:

type: Utilization

averageUtilization: 20

- type: Resource

resource:

name: memory

target:

type: AverageValue

averageValue: 30Mi

 Then apply these yamls

 kubectl apply -f .

 After that, check the nodeport

 kubectl get svc

 Finally test the autoscaler using hey command. Check the master node ip or if you are using  minikube then type minikube ip to get the ip

 hey -n 10000 -c 5 http://192.168.59.100:32681

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About Ashadullah Shawon

I am Ashadullah Shawon. I am a Software Engineer. I studied Computer Science and Engineering (CSE) at RUET. I Like To Share Knowledge. Learn More: Click Here