Learn Kubernetes Basics

Concepts

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Names

All objects in the Kubernetes REST API are unambiguously identified by a Name and a UID.

For non-unique user-provided attributes, Kubernetes provides labels and annotations.

See the identifiers design doc for the precise syntax rules for Names and UIDs.

Names

A client-provided string that refers to an object in a resource URL, such as /api/v1/pods/some-name.

Only one object of a given kind can have a given name at a time. However, if you delete the object, you can make a new object with the same name.

By convention, the names of Kubernetes resources should be up to maximum length of 253 characters and consist of lower case alphanumeric characters, -, and ., but certain resources have more specific restrictions.

For example, here’s the configuration file with a Pod name as nginx-demo and a Container name as nginx:

apiVersion: v1
kind: Pod
metadata:
  name: nginx-demo
spec:
  containers:
  - name: nginx
    image: nginx:1.7.9
    ports:
    - containerPort: 80

UIDs

A Kubernetes systems-generated string to uniquely identify objects.

Every object created over the whole lifetime of a Kubernetes cluster has a distinct UID. It is intended to distinguish between historical occurrences of similar entities.

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