This document describes ephemeral volumes in Kubernetes. Familiarity with volumes is suggested, in particular PersistentVolumeClaim and PersistentVolume. Some applications need additional storage but don't care whether that data is stored persistently across restarts. For example, caching services are often limited by memory size and can move infrequently used data into storage that is slower than memory with little impact on overall performance. Other applications expect some read-only input data to be present in files, like configuration data or secret keys.

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).

In this example, you will run a Kubernetes Job with multiple parallel worker processes. In this example, as each pod is created, it picks up one unit of work from a task queue, completes it, deletes it from the queue, and exits. Here is an overview of the steps in this example: Start a message queue service. In this example, you use RabbitMQ, but you could use another one. In practice you would set up a message queue service once and reuse it for many jobs.

This topic discusses multiple ways to interact with clusters. Accessing for the first time with kubectl When accessing the Kubernetes API for the first time, we suggest using the Kubernetes CLI, kubectl. To access a cluster, you need to know the location of the cluster and have credentials to access it. Typically, this is automatically set-up when you work through a Getting started guide, or someone else set up the cluster and provided you with credentials and a location.

FEATURE STATE: Kubernetes v1.22 [stable] (enabled by default: true) Kubernetes supports multiple appliers collaborating to manage the fields of a single object. Server-Side Apply provides an optional mechanism for your cluster's control plane to track changes to an object's fields. At the level of a specific resource, Server-Side Apply records and tracks information about control over the fields of that object. Server-Side Apply helps users and controllers manage their resources through declarative configuration.

A ServiceAccount provides an identity for processes that run in a Pod. A process inside a Pod can use the identity of its associated service account to authenticate to the cluster's API server. For an introduction to service accounts, read configure service accounts. This task guide explains some of the concepts behind ServiceAccounts. The guide also explains how to obtain or revoke tokens that represent ServiceAccounts, and how to (optionally) bind a ServiceAccount's validity to the lifetime of an API object.

This section is relevant for people adopting a new built-in sidecar containers feature for their workloads. Sidecar container is not a new concept as posted in the blog post. Kubernetes allows running multiple containers in a Pod to implement this concept. However, running a sidecar container as a regular container has a lot of limitations being fixed with the new built-in sidecar containers support. FEATURE STATE: Kubernetes v1.29 [beta] (enabled by default: true) Objectives Understand the need for sidecar containers Be able to troubleshoot issues with the sidecar containers Understand options to universally "inject" sidecar containers to any workload Before you begin You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster.

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.

This page shows how to create a Kubernetes Service object that exposes an external IP address. Before you begin Install kubectl. Use a cloud provider like Google Kubernetes Engine or Amazon Web Services to create a Kubernetes cluster. This tutorial creates an external load balancer, which requires a cloud provider. Configure kubectl to communicate with your Kubernetes API server. For instructions, see the documentation for your cloud provider. Objectives Run five instances of a Hello World application.

Objectives Scale an existing app manually using kubectl. Scaling an application You can create from the start a Deployment with multiple instances using the --replicas parameter for the kubectl create deployment command. Previously we created a Deployment, and then exposed it publicly via a Service. The Deployment created only one Pod for running our application. When traffic increases, we will need to scale the application to keep up with user demand.