Kubernetes

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.

kubectl is a command line interface for running commands against Kubernetes clusters. This overview covers kubectl syntax, describes the command operations, and provides common examples. For details about each command, including all the supported flags and subcommands, see the kubectl reference documentation. For installation instructions see installing kubectl.

To create deployment app -

kubectl run kubernetes-bootcamp --image=gcr.io/google-samples/kubernetes-bootcamp:v1 --port=8080

To Get all Deploymnets :

kubectl get deployments

 A Pod is a Kubernetes abstraction that represents a group of one or more application containers (such as Docker or rkt), and some shared resources

When we create a Deployment on Kubernetes, that Deployment creates Pods with containers inside them (as opposed to creating containers directly). Each Pod is tied to the Node where it is scheduled, and remains there until termination (according to restart policy) or deletion. In case of failures identical Pods are scheduled on other available Nodes.

kubectl get pods

kubectl desribe pods

Interface Vs Abstract Class

1. In Java you can only extend one class but implement multiple interface. So if you extend a class you lost your chance of extending another class.

2. Interface are used to represent adjective or behavior e.g. Runnable, Clonable, Serializable etc, so if you use an abstract class to represent behavior your class can not be Runnable and Clonable at same time because you can not extend two class in Java but if you use interface your class can have multiple behavior at same time.

3. On time critical application prefer abstract class is slightly faster than interface.

4. If there is a genuine common behavior across the inheritance hierarchy which can be coded better at one place than abstract class is preferred choice. Some time interface and abstract class can work together also where defining function in interface and default functionality on abstract class.

class SmartPhone

  brand: String

  year

  model

 message():abstract

calling():abstract

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inteface Camera
interface Music  
interface AppleWatch

Iphone extends SmartPhone implements Camera, Music, AppleWatch
Android extends SmartPhone implements Camera, Music
windows extends SmartPhone implements Camera, Music