How to Specify ServiceAccountName for Pods in GKE Deployment.YAML

Question

I've configured my cluster and node pools for Workload Identity (https://cloud.google.com/kubernetes-engine/docs/how-to/workload-identity) but in order to get it to work, I need to also make my pods use the kubernetes service account I created for the Workload Identity.

I see I can specify the serviceAccountName in a pod's YAML, but how can I do this using Google CI/CD which uses deployment.yaml? Or can I somehow reference a pod's YAML for use as a spec template within my deployment.yaml? Sorry, I am new to k8s!

Ref. https://kubernetes.io/docs/tasks/configure-pod-container/configure-service-account/

Essentially, I am just trying to get Workload Identity to work with my application so the GOOGLE_APPLICATION_CREDENTIALS is set by Google for use within my app!

I've tried the following in my deployment.yaml but I get the error unknown field "serviceAccountName" in io.k8s.api.core.v1.Container;:

spec:
  replicas: 3
  selector:
    matchLabels:
      app: my-application
  strategy:
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 25%
    type: RollingUpdate
  template:
    metadata:
      labels:
        app: my-application
    spec:
      containers:
        - image: >-
            gcr.io/my-project/github.com/my-org/my-repo
          imagePullPolicy: IfNotPresent
          name: my-application
          serviceAccountName: my-k8s-svc-acct

Answer 1

serviceAccountName is a property of the pod spec object, not the container. So, it should be:

spec:
  replicas: 3
  selector:
    matchLabels:
      app: my-application
  strategy:
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 25%
    type: RollingUpdate
  template:
    metadata:
      labels:
        app: my-application
    spec:
      serviceAccountName: my-k8s-svc-acct
      containers:
        - image: >-
            gcr.io/my-project/github.com/my-org/my-repo
          imagePullPolicy: IfNotPresent
          name: my-application