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:

Kubernetes volumes provide a way for containers in a pod 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.

In Kubernetes, Services are an abstract way to expose an application running on a set of Pods. Services can have a cluster-scoped virtual IP address (using a Service of type: ClusterIP). Clients can connect using that virtual IP address, and Kubernetes then load-balances traffic to that Service across the different backing Pods. How Service ClusterIPs are allocated? When Kubernetes needs to assign a virtual IP address for a Service, that assignment happens one of two ways:

Baseline checklist for ensuring security in Kubernetes clusters.

When several users or teams share a cluster with a fixed number of nodes, there is a concern that one team could use more than its fair share of resources. Resource quotas are a tool for administrators to address this concern. A resource quota, defined by a ResourceQuota object, provides constraints that limit aggregate resource consumption per namespace. A ResourceQuota can also limit the quantity of objects that can be created in a namespace by API kind, as well as the total amount of infrastructure resources that may be consumed by API objects found in that namespace.

In a Kubernetes cluster, a node can be shut down in a planned graceful way or unexpectedly because of reasons such as a power outage or something else external. A node shutdown could lead to workload failure if the node is not drained before the shutdown. A node shutdown can be either graceful or non-graceful. Graceful node shutdown The kubelet attempts to detect node system shutdown and terminates pods running on the node.

Security architecture information relating to the API server and other components

A Secret is an object that contains a small amount of sensitive data such as a password, a token, or a key. Such information might otherwise be put in a Pod specification or in a container image. Using a Secret means that you don't need to include confidential data in your application code. Because Secrets can be created independently of the Pods that use them, there is less risk of the Secret (and its data) being exposed during the workflow of creating, viewing, and editing Pods.

An issue that comes up rather frequently for new installations of Kubernetes is that a Service is not working properly. You've run your Pods through a Deployment (or other workload controller) and created a Service, but you get no response when you try to access it. This document will hopefully help you to figure out what's going wrong. Running commands in a Pod For many steps here you will want to see what a Pod running in the cluster sees.

This page describes the process of migrating from PodSecurityPolicies to the built-in PodSecurity admission controller. This can be done effectively using a combination of dry-run and audit and warn modes, although this becomes harder if mutating PSPs are used. Before you begin Your Kubernetes server must be at or later than version v1.22. To check the version, enter kubectl version. If you are currently running a version of Kubernetes other than 1.