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 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.

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

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.

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.

This page provides an overview of authentication. Users in Kubernetes All Kubernetes clusters have two categories of users: service accounts managed by Kubernetes, and normal users. It is assumed that a cluster-independent service manages normal users in the following ways: an administrator distributing private keys a user store like Keystone or Google Accounts a file with a list of usernames and passwords In this regard, Kubernetes does not have objects which represent normal user accounts.

You can constrain a Pod so that it is restricted to run on particular node(s), or to prefer to run on particular nodes. There are several ways to do this and the recommended approaches all use label selectors to facilitate the selection. Often, you do not need to set any such constraints; the scheduler will automatically do a reasonable placement (for example, spreading your Pods across nodes so as not place Pods on a node with insufficient free resources).

Details of the metric data that Kubernetes components export.

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

kubeadm init phase enables you to invoke atomic steps of the bootstrap process. Hence, you can let kubeadm do some of the work and you can fill in the gaps if you wish to apply customization. kubeadm init phase is consistent with the kubeadm init workflow, and behind the scene both use the same code. kubeadm init phase preflight Using this command you can execute preflight checks on a control-plane node.