How to run a kubernetes deployment on a node and scale on another node/pool?

I'm running an b2b application on a GKE cluster (1 pool, 2 nodes). They are normal nodes, because the uptime is critical

However, I've created a secondary pool with Spot VMs with more powerful machines, but I want to allow kubernetes to use it only for scaling purposes.

Let's take this example:

• current state - default-pool: app-1 (3 replicas)
• wanted state
  • default-pool: app-1 (3 replicas)
  • spot-pool: app-1 (5 more replicas)

I want to give my clients a little boost in performance without worrying about uptime.

PS. currently on a test cluster, after adding the Spot-pool, GKE decided to move there the entire app (I didn't have a nodeselector) and I ended up with default-pool (just system services) and spot-pool with my app

LE. I may have found a way to do it but seems a bit complicated

1. deploy initial app on default-pool using nodeSelector
2. create a clone deployment for the same app, use nodeSelector to make it used the spot-pool and scale it to the required replicas
3. use kubernetes ingress canary annotation to route traffic
4. It ain't stupid if it works :D

Result on consecutive curl

Hostname: nginx-app-6f5db95856-xm8nk
Hostname: replica-app-5658bddc5d-jpqwp
Hostname: replica-app-5658bddc5d-jpqwp
Hostname: nginx-app-6f5db95856-xm8nk
Hostname: nginx-app-6f5db95856-xm8nk
Hostname: nginx-app-6f5db95856-xm8nk
Hostname: replica-app-5658bddc5d-jpqwp
Hostname: replica-app-5658bddc5d-jpqwp
Hostname: replica-app-5658bddc5d-jpqwp
Hostname: nginx-app-6f5db95856-xm8nk
Hostname: nginx-app-6f5db95856-xm8nk
Hostname: replica-app-5658bddc5d-jpqwp
Hostname: nginx-app-6f5db95856-xm8nk