This project is based on Kubernetes, Minikube version v1.19.0, kubectl version v1.21.0, Docker version 20.10.2 running on a Linux Mint 20 Virtual Machine.

The first software needed to be installed is the host for containers: Docker. Docker’s containers can be orchestrated and deployed using Kubernetes. In order to set up a single-node Kubernetes cluster on a local machine, I can use Minikube. Minikube can be installed using:

curl -LO https://storage.googleapis.com/minikube/releases/latest/minikube-linux-amd64
sudo install minikube-linux-amd64 /usr/local/bin/minikube

Minikube requires a virtual machine Hypervisor, in this case, the Hypervisor is Docker itself.

minikube config set driver docker

The cluster can be accessed using the command-line tool kubectl.

curl -LO "https://dl.k8s.io/release/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl"
sudo install -o root -g root -m 0755 kubectl /usr/local/bin/kubectl

Now it is possible to start Minikube

minikube start

Walkthrough of Horizontal Pod autoscaler at https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale-walkthrough/ This example sends an infinite loop of queries to the php-apache service.

kubectl apply -f https://k8s.io/examples/application/php-apache.yaml
kubectl run -i --tty load-generator --rm --image=busybox --restart=Never -- /bin/sh -c "while sleep 0.01; do wget -q -O- https://php-apache; done"

In order to see how the autoscaler reacts to load I need to enable metrics-server, and get hpa information.

minikube addons enable metrics-server
kubectl get hpa

Start minikube without metrics server ( no need to scale on cpu or memory)

minikube start &&  minikube dashboard && minikube addons disable metrics-server

Install the prometheus stack

helm install [NAME] prometheus-community/kube-prometheus-stack

Port-forward Prometheus and Grafana dashboard:

kubectl port-forward svc/mon-kube-prometheus-stack-prometheus 9090
kubectl port-forward service/mon-grafana 3000:80

Install Prometheus-adapter using custom configuration:

helm install prometheus-adapter  prometheus-community/prometheus-adapter -f “CUSTOM_PROMETHEUS_ADAPTER_CONFIGURATION.yaml”

use “CUSTOM_PROMETHEUS_ADAPTER_CONFIGURATION.yaml” Apply deploy, service, service monitor and hpa with custom metrics for php-apache.

kubectl create -f "application-deploy.yaml"

use application-deploy.