So a typical k8s deployment file that I'm woking on looks like this:

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  labels:
    ...
  name: ${service-name}
spec:
  replicas: 1
  strategy:
    ...
  template:
    metadata:
       ...
    spec:
      serviceAccountName: test
      ...

the goal is to create multiple services who have access to the same serviceAccount. This structure works fine when test exists in

kubectl get serviceaccount

The question is how can I set serviceAccountName to default serviceAccount if test does not exist in the namespace (for any reason)? I don't wanna fail the deployment

I essentially need to have something like

serviceAccountName: {test:-default}

P.S. clearly I can assign a variable to serviceAccountName and parse the yaml file from outside, but wanted to see if there's a better option