You can always define replicas in your deployment. Using replicas you can manually scale-up. following .yaml file is an example

apiVersion: apps/v1
kind: ReplicaSet
metadata:
  name: frontend
  labels:
    app: guestbook
    tier: frontend
spec:
  # modify replicas according to your case
  replicas: 3
  selector:
    matchLabels:
      tier: frontend
  template:
    metadata:
      labels:
        tier: frontend
    spec:
      containers:
      - name: php-redis
        image: gcr.io/google_samples/gb-frontend:v3

You can patch the deployment. The following patches the deployment 'MY_DEPLOYMENT' to 2 replicas kubectl patch deployment MY_DEPLOYMENT -p '{"spec":{"replicas": '2'}}'

If I understand you correctly this actually can be done.

Create a simple and lightweight deployment with pod affinity and scale it up manually when you need more nodes. That way pod will not be scheduled on the node if there is the same pod scheduled already. It will remain in the pending state what makes cluster autoscaler create another node for it.

Here are some useful links:

• assign-pod-node
• affinity config guide
• nodeselector and affinity

Please let me know if that helped.