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Kubernetes Core Concepts

This page introduces the fundamental building blocks of Kubernetes.

What is Kubernetes?​

Kubernetes, often abbreviated as K8s, is an open-source container orchestration platform that automates the deployment, scaling, and management of containerized applications. It was originally designed by Google and is now maintained by the Cloud Native Computing Foundation (CNCF).

Pods​

A Pod is the smallest and simplest unit in the Kubernetes object model that you create or deploy. A Pod represents a running process on your cluster and can contain one or more containers, such as Docker containers. When a Pod runs multiple containers, the containers are managed as a single entity and share the Pod's resources.

Services​

A Service is an abstraction which defines a logical set of Pods and a policy by which to access them. Services enable a loose coupling between dependent Pods. A Service is assigned a static IP address that remains constant for the lifetime of the Service, even if the Pods it routes to are terminated and recreated.

Deployments​

A Deployment provides declarative updates for Pods and ReplicaSets. You describe a desired state in a Deployment, and the Deployment Controller changes the actual state to the desired state at a controlled rate. You can define Deployments to create new ReplicaSets, or to remove existing Deployments and adopt all their resources with new Deployments.

ReplicaSets​

A ReplicaSet's purpose is to maintain a stable set of replica Pods running at any given time. As such, it is often used to guarantee the availability of a specified number of identical Pods. You will rarely create ReplicaSets directly; instead, you will use Deployments, which manage ReplicaSets for you.

Namespaces​

Namespaces are a way to divide cluster resources between multiple users. They are intended for use in environments with many users spread across multiple teams, or projects. Namespaces provide a scope for names. Names of resources need to be unique within a namespace, but not across namespaces.