Postgres Instance level pod anti-affinity

Please, answer some short questions which should help us to understand your problem / question better?

• Which image of the operator are you using? e.g. ghcr.io/zalando/postgres-operator:v1.13.0
• https://github.com/zalando/postgres-operator/issues
• Where do you run it - cloud or metal? Kubernetes or OpenShift? [AWS K8s | GCP ... | Bare Metal K8s]
• Bare metal K8s
• Are you running Postgres Operator in production? [yes | no]
• Yes
• Type of issue? [Bug report, question, feature request, etc.]
• feature request

Summary:

Currently, the Postgres Operator allows setting pod anti-affinity rules at the cluster level, either as preferred or required. However, in large Kubernetes clusters with multiple PostgreSQL clusters running in separate node groups, a more granular level control is needed

Use Case
In our setup, we have a large Kubernetes cluster hosting multiple PostgreSQL clusters, each running on dedicated node groups. The existing cluster-wide anti-affinity setting does not provide the flexibility to define anti-affinity at an individual PostgreSQL instance level.

I'm interested in contributing this feature request to the Postgres Operator if it is beneficial to the broader community. If others needs this change or have feedback on this approach, love to collaborate and refine the solution further.

Start by reviewing how the operator currently configures cluster-level pod anti-affinity and the relevant Kubernetes scheduling behavior. The issue does not name files, tests, or an exact configuration shape; completion would require an agreed design for per-instance anti-affinity and corresponding implementation and validation.