Production-Grade Container Orchestration

Resources that Kubernetes provides for configuring Pods.

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.

A ReplicaSet's purpose is to maintain a stable set of replica Pods running at any given time. Usually, you define a Deployment and let that Deployment manage ReplicaSets automatically.

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.

FEATURE STATE: Kubernetes v1.33 [stable](enabled by default) Sidecar containers are the secondary containers that run along with the main application container within the same Pod. These containers are used to enhance or to extend the functionality of the primary app container by providing additional services, or functionality such as logging, monitoring, security, or data synchronization, without directly altering the primary application code. Typically, you only have one app container in a Pod.

The Kubernetes API server stores objects, relying on an etcd-compatible backing store (often, the backing storage is etcd itself). Each object is serialized using a particular version of that API type; for example, the v1 representation of a ConfigMap. Kubernetes uses the term storage version to describe how an object is stored in your cluster. The Kubernetes API also relies on automatic conversion; for example, if you have a HorizontalPodAutoscaler, then you can interact with that HorizontalPodAutoscaler using any mix of the v1 and v2 versions of the HorizontalPodAutoscaler API.

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.

FEATURE STATE: Kubernetes v1.23 [stable] Your Kubernetes cluster includes dual-stack networking, which means that cluster networking lets you use either address family. In a cluster, the control plane can assign both an IPv4 address and an IPv6 address to a single Pod or a Service. Before you begin You need to have installed the kubeadm tool, following the steps from Installing kubeadm. For each server that you want to use as a node, make sure it allows IPv6 forwarding.

A cluster is a set of nodes (physical or virtual machines) running Kubernetes agents, managed by the control plane. Kubernetes v1.35 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.