[sdlc] Deploy a GKE cluster and VM on the same VPC for seamless communication

Problem to solve

For sandbox environment we want to have GitLab OAK pattern: GitLab instance on the VM and adjacent services on Kubernetes cluster. The services should be able to communicate to each other and not be exposed to the external world (except for the services that explicitly need it like GitLab itself or some dashboards services).

Proposed solution

This should be easy with the GCP:

• Create shared network (VPC) that will be used by a VM.
• Create k8s cluster on this network.
• Create a VM on this network.

Or GCP might already created a network for the project and by default all resources already use it, confirm it.