Affinity rules with app.kubernetes.io/name labels

[Apollorion]

If I have a deployment that has this affinity rule:

  requiredDuringSchedulingIgnoredDuringExecution:
  - labelSelector:
      matchExpressions:                                                                                                                                                         
      - key: app.kubernetes.io/name
        operator: In
        values:
        - my-awesome-pod
    topologyKey: kubernetes.io/hostname

Flagger does not modify that value to include -primary when it updates the primary deployment. So the affinity rule only applies to the canaried deployment. Alternatively, I can also update the rule to include -primary in it. In this case, the rules only apply to the primary and not the canaried deployment.

I've thought about utilizing a different label, one that would be the same across both the canary and the primary.
The downside here is that if I have 10 pods in the deployment, it would require me to temporarily have 20 nodes because of the topologyKey since I would have 10 canaried pods and 10 primary pods.

What I'm really looking for is a way to set up something like this:

node1: my-awesome-pod, my-awesome-pod-primary 
node2: my-awesome-pod, my-awesome-pod-primary 
node3: my-awesome-pod, my-awesome-pod-primary 

instead of:

node1: my-awesome-pod, my-awesome-pod, my-awesome-pod-primary 
node2: my-awesome-pod, my-awesome-pod-primary 
node3: my-awesome-pod-primary

A suggestion would be to have Flagger parse affinity rules and add -primary to primary pods if the app.kubernetes.io/name key is found. But I wasn't sure if there was a better, simpler, way to do this.

[stefanprodan]

I think Flagger could parse the rules, extract the ones that match the label selector (can be one of app, name, app.kubernetes.io/name or something else configured at startup with --selector-labels) and append the -primary to the value. The problem is that you can have more than one value, in this case Flagger should skip the replace and log that it did so.