In addition to compiled-in admission plugins, admission plugins can be developed as extensions and run as webhooks configured at runtime. This page describes how to build, configure, use, and monitor admission webhooks. What are admission webhooks? Admission webhooks are HTTP callbacks that receive admission requests and do something with them. You can define two types of admission webhooks, validating admission webhook and mutating admission webhook. Mutating admission webhooks are invoked first, and can modify objects sent to the API server to enforce custom defaults.

This document describes persistent volumes in Kubernetes. Familiarity with volumes, StorageClasses and VolumeAttributesClasses is suggested. Introduction Managing storage is a distinct problem from managing compute instances. The PersistentVolume subsystem provides an API for users and administrators that abstracts details of how storage is provided from how it is consumed. To do this, we introduce two new API resources: PersistentVolume and PersistentVolumeClaim. A PersistentVolume (PV) is a piece of storage in the cluster that has been provisioned by an administrator or dynamically provisioned using Storage Classes.

Kubernetes objects can be created, updated, and deleted by storing multiple object configuration files in a directory and using kubectl apply to recursively create and update those objects as needed. This method retains writes made to live objects without merging the changes back into the object configuration files. kubectl diff also gives you a preview of what changes apply will make. Before you begin Install kubectl. You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster.

Glossary This glossary is intended to be a comprehensive, standardized list of Kubernetes terminology. It includes te...

This page contains an overview of the various feature gates an administrator can specify on different Kubernetes components. See feature stages for an explanation of the stages for a feature. Overview Feature gates are a set of key=value pairs that describe Kubernetes features. You can turn these features on or off using the --feature-gates command line flag on each Kubernetes component. Each Kubernetes component lets you enable or disable a set of feature gates that are relevant to that component.

This page shows how to install a custom resource into the Kubernetes API by creating a CustomResourceDefinition. Before you begin You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. It is recommended to run this tutorial on a cluster with at least two nodes that are not acting as control plane hosts. If you do not already have a cluster, you can create one by using minikube or you can use one of these Kubernetes playgrounds:

This page contains list of feature gates that have been removed. The information on this page is for reference. A removed feature gate is different from a GA'ed or deprecated one in that a removed one is no longer recognized as a valid feature gate. However, a GA'ed or a deprecated feature gate is still recognized by the corresponding Kubernetes components although they are unable to cause any behavior differences in a cluster.

This tutorial demonstrates running Apache Zookeeper on Kubernetes using StatefulSets, PodDisruptionBudgets, and PodAntiAffinity. Before you begin Before starting this tutorial, you should be familiar with the following Kubernetes concepts: Pods Cluster DNS Headless Services PersistentVolumes PersistentVolume Provisioning StatefulSets PodDisruptionBudgets PodAntiAffinity kubectl CLI You must have a cluster with at least four nodes, and each node requires at least 2 CPUs and 4 GiB of memory. In this tutorial you will cordon and drain the cluster's nodes.

Kubernetes reserves all labels and annotations in the kubernetes.io and k8s.io namespaces. This document serves both as a reference to the values and as a coordination point for assigning values. Labels, annotations and taints used on API objects apf.kubernetes.io/autoupdate-spec Type: Annotation Example: apf.kubernetes.io/autoupdate-spec: "true" Used on: FlowSchema and PriorityLevelConfiguration Objects If this annotation is set to true on a FlowSchema or PriorityLevelConfiguration, the spec for that object is managed by the kube-apiserver.

The Kubernetes API is a resource-based (RESTful) programmatic interface provided via HTTP. It supports retrieving, creating, updating, and deleting primary resources via the standard HTTP verbs (POST, PUT, PATCH, DELETE, GET). For some resources, the API includes additional subresources that allow fine grained authorization (such as separate views for Pod details and log retrievals), and can accept and serve those resources in different representations for convenience or efficiency. Kubernetes supports efficient change notifications on resources via watches.