Azure AKS - Horizontal Pod Autoscaling (HPA)¶

Link to all the Kubernetes Manifests¶

Step-01: Introduction¶

• What is Horizontal Pod Autoscaling?
• How HPA Works?
• How HPA configured?
• Metrics Server

Azure Kubernetes Service with Azure DevOps and Terraform¶

Step-02: Review Deploy our Application¶

# Deploy
kubectl apply -f kube-manifests/apps

# List Pods, Deploy & Service
kubectl get pod
kubect get svc

# Access Application (Only if our Cluster is Public Subnet)
http://<PublicIP-from-Get-SVC-Output>

Step-03: Create a Horizontal Pod Autoscaler resource for the "hpa-demo-deployment"¶

• This command creates an autoscaler that targets 20 percent CPU utilization for the deployment, with a minimum of one pod and a maximum of ten pods.
• When the average CPU load is below 20 percent, the autoscaler tries to reduce the number of pods in the deployment, to a minimum of one.
• When the load is greater than 20 percent, the autoscaler tries to increase the number of pods in the deployment, up to a maximum of ten

  # HPA Imperative - Template
  kubectl autoscale deployment <deployment-name> --cpu-percent=20 --min=1 --max=10
  
  # HPA Imperative - Replace
  kubectl autoscale deployment hpa-demo-deployment --cpu-percent=20 --min=1 --max=10
  
  # HPA Declarative (Optional - If you use above imperative command this is just for reference)
  kubectl apply -f kube-manifests/hpa-manifest/hpa-manifest.yml
  
  # Describe HPA
  kubectl describe hpa/hpa-demo-deployment 
  
  # List HPA
  kubectl get horizontalpodautoscaler.autoscaling/hpa-demo-deployment 
  

Step-04: Create the load & Verify how HPA is working¶

# Generate Load (new Terminal)
kubectl run apache-bench -i --tty --rm --image=httpd -- ab -n 500000 -c 1000 http://hpa-demo-service-nginx.default.svc.cluster.local/ 

# List all HPA
kubectl get hpa

# List specific HPA
kubectl get hpa hpa-demo-deployment 

# Describe HPA
kubectl describe hpa/hpa-demo-deployment 

# List Pods
kubectl get pods

Step-05: Cooldown / Scaledown¶

• Default cooldown period is 5 minutes.
• Once CPU utilization of pods is less than 20%, it will starting terminating pods and will reach to minimum 1 pod as configured.

Step-06: Clean-Up¶

# Delete HPA
kubectl delete hpa hpa-demo-deployment

# Delete Deployment & Service
kubectl delete -f kube-manifests/apps 

Step-07: Deploy App and HPA Declarative Manifest¶

# Deploy App
kubectl apply -f kube-manifests/apps 

# Deploy HPA Manifest
kubectl apply -f kube-manifests/hpa-manifest

Step-08: Create the load & Verify how HPA is working¶

# Generate Load
kubectl run apache-bench -i --tty --rm --image=httpd -- ab -n 500000 -c 1000 http://hpa-demo-service-nginx.default.svc.cluster.local/ 

# List all HPA
kubectl get hpa

# List specific HPA
kubectl get hpa hpa-demo-declarative

# Describe HPA
kubectl describe hpa/hpa-demo-declarative

# List Pods
kubectl get pods

Step-09: Clean-Up¶

# Delete HPA & Apps
kubectl delete -R -f kube-manifests/

# Delete Cluster, Resource Group  (Optional)
echo $RESOURCE_GROUP
az group delete -n ${RESOURCE_GROUP}

Referencess¶

• Azure AKS - Horizontal Pod Autoscaler

Best Selling Azure Kubernetes Service Course on Udemy¶

Best Selling AWS EKS Kubernetes Course on Udemy¶

HashiCorp Certified Terraform Associate - 50 Practical Demos¶