The correct option is Define a PodAntiAffinity rule that sets topologyKey to "kubernetes.io/hostname" and operator to "In". This explicitly tells the scheduler to avoid placing a pod on any node that already runs a matching pod on the same hostname.

A PodAntiAffinity term with operator "In" and topologyKey "kubernetes.io/hostname" expresses an exclusion rule based on hostnames. When used as a requiredDuringSchedulingIgnoredDuringExecution rule the scheduler will refuse to schedule a pod onto a node that already hosts a pod that matches the term and labels. That enforces that the two pods are never colocated on the same node.

Assign the same hostPort value to both pods is incorrect because hostPort is a network binding and not a declarative scheduling primitive. It can lead to runtime port conflicts or failed container start up but it is not the supported way to express placement intent to the scheduler.

Create a PodAffinity rule with topologyKey set to "kubernetes.io/hostname" and operator set to "NotIn" is incorrect because PodAffinity is intended for co locating pods and not for excluding placement. Using an affinity term with NotIn does not convey the same exclusion semantics as a PodAntiAffinity rule with operator In.

Use a NodeSelector that targets different labeled nodes for each pod is incorrect because NodeSelector enforces static label based placement and requires manual label management. It can be brittle and does not express the dynamic intent to avoid colocating pods the way PodAntiAffinity does.

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