Pod affinity and anti-affinity in Kubernetes - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is pod affinity in Kubernetes?

Pod affinity lets you tell Kubernetes to schedule pods close to other pods based on labels. It helps pods run together on the same or nearby nodes.

beginner

What does pod anti-affinity do?

Pod anti-affinity tells Kubernetes to avoid placing pods near certain other pods. It helps spread pods apart for better availability.

intermediate

Which Kubernetes field is used to specify pod affinity rules in a pod spec?

The field is affinity.podAffinity inside the pod spec's spec.affinity section.

intermediate

How do you express that a pod should not be scheduled on the same node as pods with label app=frontend?

Use pod anti-affinity with a rule matching label app=frontend and set topologyKey to kubernetes.io/hostname to avoid the same node.

advanced

What is the difference between requiredDuringSchedulingIgnoredDuringExecution and preferredDuringSchedulingIgnoredDuringExecution in pod affinity?

requiredDuringSchedulingIgnoredDuringExecution means the rule must be met to schedule the pod. preferredDuringSchedulingIgnoredDuringExecution means the rule is a soft preference but not mandatory.

What does pod affinity help you do?

A Prevent pods from running on any node

B Schedule pods close to other pods with specific labels

C Delete pods automatically

D Scale pods horizontally

Pod affinity helps schedule pods near other pods that match certain labels.

Which field defines pod anti-affinity rules?

A spec.affinity.podAntiAffinity

B spec.containers.antiAffinity

C metadata.labels.antiAffinity

D spec.nodeSelector

Pod anti-affinity rules are set under spec.affinity.podAntiAffinity.

What does setting topologyKey: kubernetes.io/hostname in pod anti-affinity do?

A Ignores node labels

B Schedules pods only on master nodes

C Forces pods to run on different clusters

D Avoids scheduling pods on the same node

This key means pods should not be scheduled on the same node (hostname).

Which affinity type is a soft preference, not mandatory?

A preferredDuringSchedulingIgnoredDuringExecution

B requiredDuringSchedulingIgnoredDuringExecution

C nodeAffinity

D podSelector

Preferred affinity is a soft rule, while required affinity is mandatory.

Pod anti-affinity is useful to:

A Run all pods on the same node

B Increase pod CPU limits

C Spread pods across nodes for high availability

D Automatically update pods

Anti-affinity helps spread pods to avoid single points of failure.

Explain how pod affinity and anti-affinity affect pod scheduling in Kubernetes.

Think about how pods can be grouped or separated on nodes.

Describe the difference between required and preferred rules in pod affinity or anti-affinity.

Consider how strict Kubernetes is when placing pods.