k3s/docs/user-guide

PLEASE NOTE: This document applies to the HEAD of the source tree

If you are using a released version of Kubernetes, you should refer to the docs that go with that version.

The latest 1.0.x release of this document can be found [here](http://releases.k8s.io/release-1.0/docs/user-guide/README.md).

Documentation for other releases can be found at releases.k8s.io.

Kubernetes User Guide: Managing Applications

Table of Contents

• Kubernetes User Guide: Managing Applications
  • Quick walkthrough
  • Thorough walkthrough
  • Concept guide
  • Further reading

The user guide is intended for anyone who wants to run programs and services on an existing Kubernetes cluster. Setup and administration of a Kubernetes cluster is described in the Cluster Admin Guide. The Developer Guide is for anyone wanting to either write code which directly accesses the Kubernetes API, or to contribute directly to the Kubernetes project.

Please ensure you have completed the prerequisites for running examples from the user guide.

Quick walkthrough

1. Kubernetes 101
2. Kubernetes 201

Thorough walkthrough

If you don't have much familiarity with Kubernetes, we recommend you read the following sections in order:

1. Quick start: launch and expose an application
2. Configuring and launching containers: configuring common container parameters
3. Deploying continuously running applications
4. Connecting applications: exposing applications to clients and users
5. Working with containers in production
6. Managing deployments
7. Application introspection and debugging
   1. Using the Kubernetes web user interface
   2. Logging
   3. Monitoring
   4. Getting into containers via exec
   5. Connecting to containers via proxies
   6. Connecting to containers via port forwarding

Concept guide

Overview

A brief overview of Kubernetes concepts.

Cluster

A cluster is a set of physical or virtual machines and other infrastructure resources used by Kubernetes to run your applications.

Node

A node is a physical or virtual machine running Kubernetes, onto which pods can be scheduled.

Pod

A pod is a co-located group of containers and volumes.

Label

A label is a key/value pair that is attached to a resource, such as a pod, to convey a user-defined identifying attribute. Labels can be used to organize and to select subsets of resources.

Selector

A selector is an expression that matches labels in order to identify related resources, such as which pods are targeted by a load-balanced service.

Replication Controller

A replication controller ensures that a specified number of pod replicas are running at any one time. It both allows for easy scaling of replicated systems and handles re-creation of a pod when the machine it is on reboots or otherwise fails.

Service

A service defines a set of pods and a means by which to access them, such as single stable IP address and corresponding DNS name.

Volume

A volume is a directory, possibly with some data in it, which is accessible to a Container as part of its filesystem. Kubernetes volumes build upon Docker Volumes, adding provisioning of the volume directory and/or device.

Secret

A secret stores sensitive data, such as authentication tokens, which can be made available to containers upon request.

Name

A user- or client-provided name for a resource.

Namespace

A namespace is like a prefix to the name of a resource. Namespaces help different projects, teams, or customers to share a cluster, such as by preventing name collisions between unrelated teams.

Annotation

A key/value pair that can hold larger (compared to a label), and possibly not human-readable, data, intended to store non-identifying auxiliary data, especially data manipulated by tools and system extensions. Efficient filtering by annotation values is not supported.

Further reading

• API resources

  • Working with resources

• Pods and containers

  • Pod lifecycle and restart policies
  • Lifecycle hooks
  • Compute resources, such as cpu and memory
  • Specifying commands and requesting capabilities
  • Downward API: accessing system configuration from a pod
  • Images and registries
  • Migrating from docker-cli to kubectl
  • Tips and tricks when working with config
  • Assign pods to selected nodes
  • Perform a rolling update on a running group of pods