I have created frontend and backend group servers in custom vpc network. Created firewall rules to allow egress traffic from frontend to backend servers group only. I am able to ping to backend servers from frontend server but from front end server when i tried to ssh to backend servers getting below error:
ERROR: (gcloud.compute.ssh) Could not fetch resource: – Required ‘compute.instances.get’ permission for ‘projects/lab-1-299910/zones/us-west1-a/instances/backend-instance-2’
It seems like an authorization issue to me. Try to execute below command to authorize gcloud to access the Cloud Platform with Google user credentials. And then try to SSH backend server.
gcloud auth login
You might have not selected the correct project, which you can set via below command before executing SSH command
gcloud config set project
Hope this helps!