Kubernetes Architecture

Introduction to Kubernetes

Frank Heilmann

Platform Architect and Freelance Instructor

Kubernetes Overview

  • Kubernetes is built from many elements:
  • Most important ones, from larger to smaller:
    • Clusters and Control Planes
    • Nodes
    • Pods
  • Network connectivity through Services
Introduction to Kubernetes

Kubernetes Cluster and the Control Plane

Kubernetes Cluster and Control Plane

  • A Kubernetes Cluster is a set of connected computers (or Nodes)
  • Servers in a datacenter, virtual machines in the cloud
  • The Kubernetes Control Plane manages these nodes
    • consists of many components, that can run on any node in the cluster
Introduction to Kubernetes

Kubernetes Nodes

Kubernetes Nodes

  • A Kubernetes Node typically runs Linux + container engine (Docker)

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  • Nodes are also called worker machines

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  • Nodes run Kubernetes Kubelet
    • ensures containers run in so-called Pods
Introduction to Kubernetes

Kubernetes Pods

Kubernetes Pods

  • Kubernetes Pod
    • Smallest unit that you can deploy
    • A Pod is a set of one or more containers
  • The containers in a Pod belong together logically, share storage and network
  • Pods are ephemeral:
    • Pods can be stopped and recreated and any point in time.
    • Pods can moved to other nodes at any point in time.
Introduction to Kubernetes

Kubernetes Services

Kubernetes Services

  • Kubernetes Service: resource for exposing network connectivity
  • Required to connect to Pod from outside, or to communicate between Pods
  • Reason: Pods may get re-deployed any time, and will
    • Receive a new IP address
  • Services are not ephemeral, they offer stable network connectivity
Introduction to Kubernetes

Kubernetes Cheat Sheet

  • Kubernetes Cluster: set of connected computers (Nodes) configured to run Kubernetes
  • Kubernetes Control Plane: manages the Nodes in a Cluster
  • Kubernetes Nodes: also called "worker machines", running Linux and a container engine
  • Kubernetes Pods: a set of one or more containers, the smallest deployable unit
  • Kubernetes Services: a resource for exposing network connectivity, required to connect to Pods from outside, and for communication between Pods
Introduction to Kubernetes

Let's practice!

Introduction to Kubernetes

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