Kubernetes: The one true control plane to save them all

Kubernetes, also known as K8s, is an open-source container orchestration platform that allows developers to deploy and manage containerized applications at scale. It was originally developed by Google and released as an open-source project in 2014.

Kubernetes is built on top of Docker, a containerization technology that allows developers to package applications and their dependencies into lightweight, portable containers. These containers can then be easily deployed on any platform, making it easier to develop and maintain applications.

One of the main benefits of using Kubernetes is its ability to automate the deployment, scaling, and management of containerized applications. This allows developers to focus on writing code and delivering value to their users, rather than worrying about the underlying infrastructure.

To get started with Kubernetes, you will need to install a cluster of machines, known as nodes, that will host your containerized applications. These nodes can be physical servers or virtual machines, and can be located on-premises or in the cloud.

Once you have your nodes set up, you can deploy your applications by creating a deployment configuration file in YAML format. This file specifies the desired state of your application, including the number of replicas you want to run, the container image to use, and any environment variables or other configuration settings.

Here is an example deployment configuration file for a simple Node.js application:

apiVersion: apps/v1
kind: Deployment
kind: Deployment
metadata:
  name: my-app
spec:
  replicas: 2
  selector:
    matchLabels:
      app: my-app
  template:
    metadata:
      labels:
        app: my-app
    spec:
      containers:
      - name: my-app
        image: node:12-alpine
        ports:
        - containerPort: 3000

To deploy this application, you would use the kubectl command-line tool, which is the primary way to interact with a Kubernetes cluster. You can use the kubectl apply command to apply the configuration file to your cluster:

kubectl apply -f deployment.yaml

Once your deployment is up and running, you can use the kubectl get command to view the current status of your application:

kubectl get deployments

This will show you the number of replicas that are currently running, as well as any other relevant information about your deployment.

In addition to deployments, Kubernetes also supports other resource types, such as services, pods, and volumes. Services allow you to expose your application to the outside world, while pods are the basic unit of execution in Kubernetes, representing a single instance of your application. Volumes allow you to persist data beyond the lifetime of a single pod, making it easier to manage stateful applications.

One of the key features of Kubernetes is its ability to automate the scaling of your applications. You can use the kubectl scale command to adjust the number of replicas in your deployment:

kubectl scale deployment my-app --replicas=4

Kubernetes will then automatically create or destroy replicas as needed to meet the desired number of replicas. This makes it easy to scale your applications up or down based on demand.

Kubernetes has become the de facto standard for container orchestration, and is used by many