Getting to know kubernetes


Kubernetes, first and foremost is an open source platform for automating container operations. It allows you to automate deployments and scale and manage your containzerized applications. In order to run containers, k8s uses a container runtime. Most commonly Docker is used, but it also supports others such as CRI-O and Containerd.

k8s image

What is it?

Kubernetes is quite powerful and the list of what it can do is long:


Kubernetes has a concept of objects which operate on a “record of intent” which means once you create an object k8s will work to ensure that object exists. Said another way, you provide a desired state and k8s will look to match that described desired state. The basic objects to know are:

apiVersion: v1
kind: Service
  name: my-service
    app: MyApp
    - protocol: TCP
      port: 80
      targetPort: 9376

And see the deployment file that will provide the pod:

apiVersion: apps/v1
kind: Deployment
  name: MyApp
  replicas: 1
      app: MyApp
        app: MyApp

There are controllers provided by k8s which are built upon basic k8s objects:

Docker vs. Kubernetes

Docker provides a standard for packaging and distributing containerized applications. Kubernetes provides a framework for coordinate and schedule these applications. Docker runs on a single node while k8s is designed to run across a cluster. By default Docker uses host-private networking so containers can talk to each other only if they’re on the same machine. Therefore in order for Docker containers to communicate across nodes certain ports must be allocated on the machine’s IP and then forwarded or proxied to the containers. This can prove to be difficult to manage and coordinate at scale. In k8s each pod gets its own cluster-private IP address so explicit links between pods isn’t needed to connect them. When running a pod with a service a tool called kubelet adds a set of environment variables for each active Service.

In general when talking about the two, Docker can be seen as a potential ground on which k8s sits and is built upon.

Hungry for more kubernetes content and resources? Check out Awesome kubernetes for all of the k8s resources you could ever dream of!