Motivation for this project.

• To get to know how to do Horizontal Scaling of Containerized application using Kubernetes. This example provides a demonstration on Horizontal Pods Autoscaling(HPA) on a node application.

How to set up the environment and required tools?

1. Docker for Mac/Ubuntu/Windows.

   • This is used for creating a containerized application and pushing an image to DockerHub to access it in Kubernetes configuration. You can also use a locally built image. But it is always better to push DockerHub to have an ease of access anywhere whether locally or AWS.

   • for Mac, install Docker for Moc

2. Minikube

   • Minikube is a tool that makes it easy to run Kubernetes locally. Minikube runs a single-node Kubernetes cluster inside a VM on your laptop for users looking to try out Kubernetes or develop with it day-to-day. [https://github.com/kubernetes/minikube]

   • for Mac, brew cask install minikube

3. VirtualBox

   • Virtual Box is used by Minikube to run a virtual machine for cluster set up purpose.

   • for Mac, brew cask install virtualbox

4. Kubectl

   • Kubectl is the command-line interface that lets you interact with Kuberentes. Run brew install kubectl in your Terminal.

   • Minikube will automatically install it as a dependency.

Steps to run the sample HPA after installing required tools.

• Below steps are to setting up Minikube.

  • Run minikube start. This command will take time on first run.
  • Check Kubectl installation by running kubectl version
  • Enable metrics-server using minikube addons enable metrics-server
    • metrics-server is used for monitoring the pod resource. e.g CPU utilization, memory
    • check the metrics-server using kubectl top node, enabling can take few seconds, so be patient
  • If enabling metrics-server doesn't work try this step:
    • git clone https://github.com/kubernetes-incubator/metrics-server.git
    • cd metrics-server
    • kubectl create -f deploy/1.8+/
    • check the metrics-server using kubectl top node

• Clone this project

  • be in root of my project, Run kubectl apply -f k8s
  • Open new terminal Run minikube dashboard to open Kubernetes dashboard
  • Run minikube service node-example to check the node-app pod(container) is working or not
  • Check HPA demo live:
    • Open three different terminal
    • Install watch if not installed using brew install watch.
    • Terminal 1 -> Run watch -n 1 kubectl get pods
    • Terminal 2 -> Run watch -n 1 kubectl get hpa
    • Terminal 3 -> Run ab -c 5 -n 1000 -t 100000 http://192.168.99.100:30001/. Used Apache Benchmark here.
    • You can see authoscalling of pods in Terminal-1.