Ensuring at least one ingress-nginx per kubernetes node

I'm trying to write an autoscaling configuration for ingress-nginx, deployed via helm chart.

my goals are:

• 3 minimum replicas (because I have 3 nodes minimum)
• ensure only one nginx per node, but:
• be elastic, if autoscale says we need 4 nginx allow for a node in the cluster to have 2
• if a fourth node gets added, ensure a new nginx gets spawned

https://github.com/kubernetes/ingress-nginx/blob/main/charts/ingress-nginx/values.yaml#L326 https://github.com/kubernetes/ingress-nginx/blob/main/charts/ingress-nginx/values.yaml#L343 https://github.com/kubernetes/ingress-nginx/blob/main/charts/ingress-nginx/values.yaml#L256

I tried playing with the below settings and a combination of them but there's always something off, for example right now I have a fourth nginx that want to spawn for some reason and it can't because of the antiaffinity rule.

Can anyone share some ideas how to achieve that?

• always one nginx per node, if a new node gets created, a new nginx gets created
• preserve autoscaling, if hpa wants to spawn a fourth nginx on a 3 node cluster it should be free to do so

      replicaCount: 3
      affinity:
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
          - labelSelector:
              matchExpressions:
              - key: app.kubernetes.io/name
                operator: In
                values:
                - ingress-nginx
              - key: app.kubernetes.io/instance
                operator: In
                values:
                - ingress-nginx
              - key: app.kubernetes.io/component
                operator: In
                values:
                - controller
            topologyKey: "kubernetes.io/hostname"

      topologySpreadConstraints:
        - maxSkew: 1
          topologyKey: topology.kubernetes.io/zone
          whenUnsatisfiable: ScheduleAnyway
          labelSelector:
            matchLabels:
              app.kubernetes.io/instance: ingress-nginx

      autoscaling:
        enabled: true
        minReplicas: 3
        maxReplicas: 6
        targetCPUUtilizationPercentage: 75
        targetMemoryUtilizationPercentage: 100