You can switch the cluster/configuration context using the following command:[desk@cli] $ kubectl config use-context qa Context:A pod...

[desk@cli] $ k create sa backend-qa -n qa

sa/backend-qa created

[desk@cli] $ k get role,rolebinding -n qa

No resources found in qa namespace.

[desk@cli] $ k create role backend -n qa --resource pods,namespaces,configmaps --verb list

# No access to secret

[desk@cli] $ k create rolebinding backend -n qa --role backend --serviceaccount qa:backend-qa

[desk@cli] $ vim /home/cert_masters/frontend-pod.yaml

apiVersion: v1

kind: Pod

metadata:

 name: frontend

spec:

 serviceAccountName: backend-qa # Add this

  image: nginx

  name: frontend

[desk@cli] $ k apply -f /home/cert_masters/frontend-pod.yaml

pod created

[desk@cli] $ k create sa backend-qa -n qa

serviceaccount/backend-qa created

[desk@cli] $ k get role,rolebinding -n qa

No resources found in qa namespace.

[desk@cli] $ k create role backend -n qa --resource pods,namespaces,configmaps --verb list

role.rbac.authorization.k8s.io/backend created

[desk@cli] $ k create rolebinding backend -n qa --role backend --serviceaccount qa:backend-qa

rolebinding.rbac.authorization.k8s.io/backend created

[desk@cli] $ vim /home/cert_masters/frontend-pod.yaml

apiVersion: v1

kind: Pod

metadata:

 name: frontend

spec:

 serviceAccountName: backend-qa # Add this

  image: nginx

  name: frontend

[desk@cli] $ k apply -f /home/cert_masters/frontend-pod.yaml

pod/frontend created

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