This page describes running Kubernetes across multiple zones. Background Kubernetes is designed so that a single Kubernetes cluster can run across multiple failure zones, typically where these zones fit within a logical grouping called a region. Major cloud providers define a region as a set of failure zones (also called availability zones) that provide a consistent set of features: within a region, each zone offers the same APIs and services.

A cluster is a set of nodes (physical or virtual machines) running Kubernetes agents, managed by the control plane. Kubernetes v1.30 supports clusters with up to 5,000 nodes. More specifically, Kubernetes is designed to accommodate configurations that meet all of the following criteria: No more than 110 pods per node No more than 5,000 nodes No more than 150,000 total pods No more than 300,000 total containers You can scale your cluster by adding or removing nodes.

This page explains the two options for configuring the topology of your highly available (HA) Kubernetes clusters. You can set up an HA cluster: With stacked control plane nodes, where etcd nodes are colocated with control plane nodes With external etcd nodes, where etcd runs on separate nodes from the control plane You should carefully consider the advantages and disadvantages of each topology before setting up an HA cluster.

This website contains documentation for the current version of Kubernetes and the four previous versions of Kubernetes. The availability of documentation for a Kubernetes version is separate from whether that release is currently supported. Read Support period to learn about which versions of Kubernetes are officially supported, and for how long.

The Concepts section helps you learn about the parts of the Kubernetes system and the abstractions Kubernetes uses to represent your cluster, and helps you obtain a deeper understanding of how Kubernetes works.

This document describes projected volumes in Kubernetes. Familiarity with volumes is suggested. Introduction A projected volume maps several existing volume sources into the same directory. Currently, the following types of volume sources can be projected: secret downwardAPI configMap serviceAccountToken clusterTrustBundle All sources are required to be in the same namespace as the Pod. For more details, see the all-in-one volume design document. Example configuration with a secret, a downwardAPI, and a configMap pods/storage/projected-secret-downwardapi-configmap.

This document catalogs the communication paths between the API server and the Kubernetes cluster. The intent is to allow users to customize their installation to harden the network configuration such that the cluster can be run on an untrusted network (or on fully public IPs on a cloud provider). Node to Control Plane Kubernetes has a "hub-and-spoke" API pattern. All API usage from nodes (or the pods they run) terminates at the API server.

FEATURE STATE: Kubernetes v1.11 [beta] Cloud infrastructure technologies let you run Kubernetes on public, private, and hybrid clouds. Kubernetes believes in automated, API-driven infrastructure without tight coupling between components. The cloud-controller-manager is a Kubernetes control plane component that embeds cloud-specific control logic. The cloud controller manager lets you link your cluster into your cloud provider's API, and separates out the components that interact with that cloud platform from components that only interact with your cluster.

This page provides an overview of init containers: specialized containers that run before app containers in a Pod. Init containers can contain utilities or setup scripts not present in an app image. You can specify init containers in the Pod specification alongside the containers array (which describes app containers). In Kubernetes, a sidecar container is a container that starts before the main application container and continues to run. This document is about init containers: containers that run to completion during Pod initialization.

Concepts and resources behind networking in Kubernetes.