---
title: Affinity
id: affinity
date: 2019-01-11
full_link: /docs/concepts/scheduling-eviction/assign-pod-node/#affinity-and-anti-affinity
short_description: >
     Rules used by the scheduler to determine where to place pods
aka:
tags:
- fundamental
---

In Kubernetes, _affinity_ is a set of rules that give hints to the scheduler about where to place pods.

<!--more-->
There are two kinds of affinity:
* [node affinity](/docs/concepts/scheduling-eviction/assign-pod-node/#node-affinity)
* [pod-to-pod affinity](/docs/concepts/scheduling-eviction/assign-pod-node/#inter-pod-affinity-and-anti-affinity)

The rules are defined using the Kubernetes {{< glossary_tooltip term_id="label" text="labels">}},
and {{< glossary_tooltip term_id="selector" text="selectors">}} specified in {{< glossary_tooltip term_id="pod" text="pods" >}}, 
and they can be either required or preferred, depending on how strictly you want the scheduler to enforce them.