What rules should be used to assign affinity to Kubernetes pods for distributing the pods across all Availability Zones? I have a region with 3 Availability Zones and Nodes in each of these. I want to make sure that each of the 3 pods are spread across all the 3 Availability Zones.
You should be able to use the label topology.kubernetes.io/zone (for e.g. topologyKey) and add anti-affinity rules.
This is part of the anti-affinity example:
podAntiAffinity:
preferredDuringSchedulingIgnoredDuringExecution:
- weight: 100
podAffinityTerm:
labelSelector:
matchExpressions:
- key: security
operator: In
values:
- S2
topologyKey: failure-domain.beta.kubernetes.io/zonethe result of the example is documented as
The pod anti-affinity rule says that the pod cannot be scheduled onto a node if that node is in the same zone as a pod with label having key "security" and value "S2".
Instead of the label security in the example, you can use e.g. app-name: <your-app-name> as label and use that in your matchExpression.