I've got a CPU-intensive serverless function deployed on a Kubernetes cluster (running on OpenFaaS). What I'd like to achieve is that whenever my function is invoked, a new node spins up in my cluster to execute the process, as multiple processes might be executed at a given time. I've so far created an HPA, set to 70% of CPU utilisation:

apiVersion: autoscaling/v2beta1
kind: HorizontalPodAutoscaler
metadata:
  name: 4d-as
  namespace: openfaas-fn
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: process-layer
  minReplicas: 1
  maxReplicas: 5
  metrics:
  - type: Resource
    resource:
      name: cpu
      targetAverageUtilization: 70

I've also added a podAntiAffinity rule to the deployment make sure only a single replica is deployed on a given node:

spec:
  affinity:
    podAntiAffinity:
      requiredDuringSchedulingIgnoredDuringExecution:
      - labelSelector:
          matchExpressions:
          - key: app
            operator: In
            values:
            - process-layer
        topologyKey: kubernetes.io/hostname

The deployment also has resource configuration settings:

requests:
  cpu: 400m
  memory: 1000Mi
limits:
  cpu: 1000m
  memory: 2000Mi

So far I was able to get new nodes spun up, with a replica of my function deployed on each. The desired outcome is that each node executes the serverless function isolated from each other. For example:

Function invoked with parameter A -> Node 1 executes the function with parameter A
Function invoked with parameter B -> Node 2 executes the function with parameter B
Function invoked with parameter C -> Node 3 executes the function with parameter C
...

Instead what I'm seeing is that Node 1 executes the function with parameter A, it then starts to execute the function with parameter B. After CPU utilisation goes above 70%, Node 2 spins up and starts to execute my function multiple times, using parameters A and B.

What I'd like instead is that Node 1 executes my function using parameter A only, Node 2 executes my function using parameter B only, and so on.

Is there a way to achieve the above?