Kubernetes requires PKI certificates for authentication over TLS. If you install Kubernetes with kubeadm, the certificates that your cluster requires are automatically generated. You can also generate your own certificates -- for example, to keep your private keys more secure by not storing them on the API server. This page explains the certificates that your cluster requires. How certificates are used by your cluster Kubernetes requires PKI for the following operations:

This page introduces Quality of Service (QoS) classes in Kubernetes, and explains how Kubernetes assigns a QoS class to each Pod as a consequence of the resource constraints that you specify for the containers in that Pod. Kubernetes relies on this classification to make decisions about which Pods to evict when there are not enough available resources on a Node. Quality of Service classes Kubernetes classifies the Pods that you run and allocates each Pod into a specific quality of service (QoS) class.

This page describes the lifecycle of a Pod. Pods follow a defined lifecycle, starting in the Pending phase, moving through Running if at least one of its primary containers starts OK, and then through either the Succeeded or Failed phases depending on whether any container in the Pod terminated in failure. Like individual application containers, Pods are considered to be relatively ephemeral (rather than durable) entities. Pods are created, assigned a unique ID (UID), and scheduled to run on nodes where they remain until termination (according to restart policy) or deletion.

Field selectors let you select Kubernetes objects based on the value of one or more resource fields. Here are some examples of field selector queries: metadata.name=my-service metadata.namespace!=default status.phase=Pending This kubectl command selects all Pods for which the value of the status.phase field is Running: kubectl get pods --field-selector status.phase=Running Note:Field selectors are essentially resource filters. By default, no selectors/filters are applied, meaning that all resources of the specified type are selected.

Each object in your cluster has a Name that is unique for that type of resource. Every Kubernetes object also has a UID that is unique across your whole cluster. For example, you can only have one Pod named myapp-1234 within the same namespace, but you can have one Pod and one Deployment that are each named myapp-1234. For non-unique user-provided attributes, Kubernetes provides labels and annotations. Names A client-provided string that refers to an object in a resource URL, such as /api/v1/pods/some-name.

This document describes the concept of cloning existing CSI Volumes in Kubernetes. Familiarity with Volumes is suggested. Introduction The CSI Volume Cloning feature adds support for specifying existing PVCs in the dataSource field to indicate a user would like to clone a Volume. A Clone is defined as a duplicate of an existing Kubernetes Volume that can be consumed as any standard Volume would be. The only difference is that upon provisioning, rather than creating a "new" empty Volume, the back end device creates an exact duplicate of the specified Volume.

Concepts for keeping your cloud-native workload secure.

In Kubernetes, scheduling refers to making sure that Pods are matched to Nodes so that Kubelet can run them. Scheduling overview A scheduler watches for newly created Pods that have no Node assigned. For every Pod that the scheduler discovers, the scheduler becomes responsible for finding the best Node for that Pod to run on. The scheduler reaches this placement decision taking into account the scheduling principles described below.

Application logs can help you understand what is happening inside your application. The logs are particularly useful for debugging problems and monitoring cluster activity. Most modern applications have some kind of logging mechanism. Likewise, container engines are designed to support logging. The easiest and most adopted logging method for containerized applications is writing to standard output and standard error streams. However, the native functionality provided by a container engine or runtime is usually not enough for a complete logging solution.

FEATURE STATE: Kubernetes v1.31 [beta] (enabled by default: false) This document shares how to extend the existing Service IP range assigned to a cluster. 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.