I have a VPC called 'subnet-1' where I have 3 VM Instances and 1 SQL Instance (Postgresql to be precise). All of them with no Public IP, just Private IP. They are in a kubernetes cluster.
The requirement I have is to be able to connect to the VPC from my on-premise PC in order to use some SQLClient to connect to the PG and see the data, I have read about CloudVPN but don't know how to configure it to have what I want... does anyone of you ever done some configuration like that?
You can use Cloud VPN but that is a site-to-site VPN that requires supported routers and solid knowledge of routing, networking and VPNs.
Using third-party VPNs with Cloud VPN
For small businesses or home based developers that only need to connect a few users to a VPC, use an open source product like OpenVPN. Google Marketplace offers a deployable configuration for your project with a click configuration. Simple and easy to deploy.