During kubeadm init, kubeadm uploads the ClusterConfiguration object to your cluster in a ConfigMap called kubeadm-config in the kube-system namespace. This configuration is then read during kubeadm join, kubeadm reset and kubeadm upgrade. You can use kubeadm config print to print the default static configuration that kubeadm uses for kubeadm init and kubeadm join. Note:The output of the command is meant to serve as an example. You must manually edit the output of this command to adapt to your setup.

Production-Grade Container Orchestration

Manage security and best-practices with policies.

Removed feature PodSecurityPolicy was deprecated in Kubernetes v1.21, and removed from Kubernetes in v1.25. Instead of using PodSecurityPolicy, you can enforce similar restrictions on Pods using either or both: Pod Security Admission a 3rd party admission plugin, that you deploy and configure yourself For a migration guide, see Migrate from PodSecurityPolicy to the Built-In PodSecurity Admission Controller. For more information on the removal of this API, see PodSecurityPolicy Deprecation: Past, Present, and Future.

Baseline checklist for ensuring security in Kubernetes clusters.

This page describes the maximum number of volumes that can be attached to a Node for various cloud providers. Cloud providers like Google, Amazon, and Microsoft typically have a limit on how many volumes can be attached to a Node. It is important for Kubernetes to respect those limits. Otherwise, Pods scheduled on a Node could get stuck waiting for volumes to attach. Kubernetes default limits The Kubernetes scheduler has default limits on the number of volumes that can be attached to a Node:

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.

Kubernetes volumes provide a way for containers in a pods to access and share data via the filesystem. There are different kinds of volume that you can use for different purposes, such as: populating a configuration file based on a ConfigMap or a Secret providing some temporary scratch space for a pod sharing a filesystem between two different containers in the same pod sharing a filesystem between two different pods (even if those Pods run on different nodes) durably storing data so that it stays available even if the Pod restarts or is replaced passing configuration information to an app running in a container, based on details of the Pod the container is in (for example: telling a sidecar container what namespace the Pod is running in) providing read-only access to data in a different container image Data sharing can be between different local processes within a container, or between different containers, or between Pods.

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.

Concepts and resources behind networking in Kubernetes.