Making Liqo multi-tenancy aware

[prometherion]

I'll try to explain my use case, even though I will use the wrong terminology, sorry in advance.

• Tenant cluster: the main cluster used by a developer
• Shared cluster: a Service cluster

In my use case, multiple Tenants are looking to offload some workloads to a shared cluster due to capacity burst, such as insufficient resources, hybrid cloud scaling, etc.

The current Liqo implementation, AFAIK, doesn't support mixing workloads from multiple Tenants, which means the Shared cluster can be consumed just by a single Tenant.

Besides the technical considerations about multi-tenancy, such as policies, noisy neighbours, and security, it would be great if each Tenant would be able to spin workloads on the Shared cluster: the latter issues could be solved by policy engines, such as Kyverno, Capsule, or other projects.

Furthermore, it's not just a matter of Pod scheduling, it's also about Network: workloads from each Tenant should be able to communicate with each other and with the ones from their Tenant. I think this could be possible by forcing the allocation of Tenant pods on specific Node pools to simplify the gateway routing, but I'm happy to start a discussion to work further.

I'm sharing a very low-quality diagram, hope it helps to share my vision.