Is there something like: kubectl get pods --project=PROJECT_ID
I would like not to modify my default gcloud configuration to switch between my staging and production environment.
kubectl saves clusters/contexts in its configuration. If you use the default scripts to bring up the cluster, these entries should've been set for your clutser.
A brief overview of kubectl config:
kubectl config view let you to view the cluster/contexts in your configuration.kubectl config set-cluster and kubectl config set-context modifies/adds new entries.You can use kubectl config use-context to change the default context, and kubectl --context=CONTEXT get pods to switch to a different context for the current command.
You can download credentials for each of your clusters using gcloud container clusters get-credentials which takes the --project flag. Once the credentials are cached locally, you can use the --context flag (as Yu-Ju explains in her answer) to switch between clusters for each command.