You can use Kubernetes annotations to attach arbitrary non-identifying metadata to objects. Clients such as tools and libraries can retrieve this metadata. Attaching metadata to objects You can use either labels or annotations to attach metadata to Kubernetes objects. Labels can be used to select objects and to find collections of objects that satisfy certain conditions. In contrast, annotations are not used to identify and select objects. The metadata in an annotation can be small or large, structured or unstructured, and can include characters not permitted by labels.

Node Conformance Test Node conformance test is a containerized test framework that provides a system verification and functionality test for a node. The test validates whether the node meets the minimum requirements for Kubernetes; a node that passes the test is qualified to join a Kubernetes cluster. Node Prerequisite To run node conformance test, a node must satisfy the same prerequisites as a standard Kubernetes node. At a minimum, the node should have the following daemons installed:

Kubernetes is an open source container orchestration engine for automating deployment, scaling, and management of containerized applications. The open source project is hosted by the Cloud Native Computing Foundation.

By default, kubeadm runs a local etcd instance on each control plane node. It is also possible to treat the etcd cluster as external and provision etcd instances on separate hosts. The differences between the two approaches are covered in the Options for Highly Available topology page. This task walks through the process of creating a high availability external etcd cluster of three members that can be used by kubeadm during cluster creation.

This document highlights and consolidates configuration best practices that are introduced throughout the user guide, Getting Started documentation, and examples. This is a living document. If you think of something that is not on this list but might be useful to others, please don't hesitate to file an issue or submit a PR. General Configuration Tips When defining configurations, specify the latest stable API version. Configuration files should be stored in version control before being pushed to the cluster.

Understand Pods, the smallest deployable compute object in Kubernetes, and the higher-level abstractions that help you to run them.

This page describes security considerations and best practices specific to the Windows operating system. Protection for Secret data on nodes On Windows, data from Secrets are written out in clear text onto the node's local storage (as compared to using tmpfs / in-memory filesystems on Linux). As a cluster operator, you should take both of the following additional measures: Use file ACLs to secure the Secrets' file location. Apply volume-level encryption using BitLocker.

The architectural concepts behind Kubernetes.

The CRI is a plugin interface which enables the kubelet to use a wide variety of container runtimes, without having a need to recompile the cluster components. You need a working container runtime on each Node in your cluster, so that the kubelet can launch Pods and their containers. The Container Runtime Interface (CRI) is the main protocol for the communication between the kubelet and Container Runtime. The Kubernetes Container Runtime Interface (CRI) defines the main gRPC protocol for the communication between the node components kubelet and container runtime.

This page shows how to configure liveness, readiness and startup probes for containers. For more information about probes, see Liveness, Readiness and Startup Probes The kubelet uses liveness probes to know when to restart a container. For example, liveness probes could catch a deadlock, where an application is running, but unable to make progress. Restarting a container in such a state can help to make the application more available despite bugs.