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](/docs/admin/). The [Developer Guide](https://github.com/kubernetes/kubernetes/tree/{{page.githubbranch}}/docs/devel) 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](/docs/user-guide/prereqs/).
: 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.
: 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.
: 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](https://docs.docker.com/userguide/dockervolumes/), adding provisioning of the volume directory and/or device.
: 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.
: 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.
* [Compute resources, such as cpu and memory](/docs/user-guide/compute-resources/)
* [Specifying commands and requesting capabilities](/docs/user-guide/containers/)
* [Downward API: accessing system configuration from a pod](/docs/user-guide/downward-api/)
* [Images and registries](/docs/user-guide/images/)
* [Migrating from docker-cli to kubectl](/docs/user-guide/docker-cli-to-kubectl/)
* [Configuration Best Practices and Tips](/docs/user-guide/config-best-practices/)
* [Assign pods to selected nodes](https://github.com/kubernetes/kubernetes.github.io/tree/{{page.docsbranch}}/docs/user-guide/node-selection/)
* [Perform a rolling update on a running group of pods](https://github.com/kubernetes/kubernetes.github.io/tree/{{page.docsbranch}}/docs/user-guide/update-demo/)