Kubernetes & Docker

I got containers on containers on containers on containers on containers

Kubernetes is a container orchestration framework that helps with managing applications requiring one or more container. You create a cluster which holds nodes which holds pods.

Pods that are running inside Kubernetes are running on a private, isolated network. By default they are visible from other pods and services within the same Kubernetes cluster, but not outside that network. When we use kubectl, we're interacting through an API endpoint to communicate with apps.

Kubernetes

minikube version
minikube start
kubectl version 
kubectl cluster-info
kubectl get #List resources
kubectl get nodes
kubectl describe  #Show details
kubectl logs #Print logs from a container in a pod
kubectl get pods
kubectl exec POD-NAME -- whoami #Execute command on a container in a pod
kubectl exec -ti POD-NAME -- /bin/bash #Execute command on a container in a pod

kubectl create deployment DEPLOYMENT-NAME --image=DOCKER-IMAGE/DOCK-USER:latest
kubectl get deployments

Pods, nodes, and deployments

When deploying, Kubernetes creates a Pod to host your application instance. A Pod is a Kubernetes abstraction that represents a group of one or more application containers (such as Docker), and some shared resources for those containers. Those resources include:

• Shared storage, as Volumes

• Networking, as a unique cluster IP address

• Information about how to run each container, such as the container image version or specific ports to use

Learn more here: https://kubernetes.io/docs/tutorials/kubernetes-basics/explore/explore-intro/

When deploying an app through kubectl, Kubernetes will do a couple of things:

• searched for a suitable node where an instance of the application could be run (we have only 1 available node)

• scheduled the application to run on that Node

• configured the cluster to reschedule the instance on a new Node when needed

Docker

docker login #Credentials 
docker pull DOCKER-IMAGE/DOCK-USER:latest