DevOps Classroom notes 11/Feb/2024

HPA (Horizontal Pod Autoscaling)

• For this to work we need metrics server to be running.
• Refer Here for hpa official docs
• Lets create a nginx deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.14.2
        ports:
        - containerPort: 80
        resources:
          limits:
            cpu: 250m
            memory: 256Mi
       - name: alpine
         image: alpine
         args:
           - sleep
           - 1d

• Lets create a hpa kubectl autoscale deployment nginx-deployment --cpu-percent=50 --min=1 --max=10

apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
  name: nginx-deployment
spec:
  maxReplicas: 10
  metrics:
  - resource:
      name: cpu
      target:
        averageUtilization: 50
        type: Utilization
    type: Resource
  minReplicas: 1
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: nginx-deployment

• Lets create a service called as nginx with cluster ip

apiVersion: v1
kind: Service
metadata:
  name: nginx-svc
spec:
  selector:
    app: nginx
  ports:
  - name: websvc
    protocol: TCP
    port: 80
    targetPort: 80

• Lets make the application busy

kubectl run -i --tty load-generator --rm --image=busybox:1.28 --restart=Never -- /bin/sh -c "while sleep 0.01; do wget -q -O- http://nginx-svc; done"

• Now watch number of pods

Cluster Autoscaler

• Every Managed k8s has a cluster autoscaler
  • AKS Refer Here
  • EKS Refer Here
• There are some of the toolings around autoscaling
  • Karpenter Refer Here
  • keda based autoscaling Refer Here

Kubernetes Lens (UI Based Client)

• Refer Here and download

Helm – Package Manager for k8s

• Chart: An Application/Component to be deployed
• Repository: This hosts Charts
• Try installing
  • wordpress
  • prometheus and grafana
  • redis cache
• To Author:
  • Go Template
  • use helm playground