Kubernetes

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An Open source Container Orchestration platform

Automates

  • Deployment of containers
  • Scaling of containers
  • Maintenance of containers

k8s_cluster_small.png

https://github.com/ByteByteGoHq/system-design-101?tab=readme-ov-file#what-is-k8s-kubernetes

Minikube

https://minikube.sigs.k8s.io/docs/handbook/controls/

brew install minikube

Start/shutdown the cluster

minikube start
minikube stop # Saves the state
minikube delete # Deletes everything

Dashboard

minikube dashboard

K8S - Important Commands

Create a namespace

kubectl create ns non-prod

Check running pod

#IpAddress, port, clusterId etc
kubectl get service

# Get podname, status
kubectl get pods # podname from minikube dashboard can also be used

#Get details like IP addres, status
kubectl describe pod <pod_name>
kubectl describe pod todo-service-app-todo-app-7b45c8749b-ltmfw

Access from Another Pod

use a temporary pod to check if the application is reachable from within the cluster

-i -t flag Allows us to provide input to the container

kubectl run -it --rm --restart=Never busybox --image=busybox -- sh

Then, inside the busybox shell, try to curl your application:

wget -qO- http://<your-pod-ip>:<port-number>/actuator/health

wget -qO- http://10.109.198.72:5000/actuator/health

Check Resource Usage

kubectl top pod <pod-name>
kubectl top pod todo-service-app-todo-app-7b45c8749b-ltmfw

Check Application logs

kubectl logs <pod-name>
kubectl logs todo-service-app-todo-app-7b45c8749b-ltmfw

# Running log
kubectl logs -f todo-service-app-todo-app-7b45c8749b-ltmfw

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