Reducing the risk
Hardening
A shared Kubernetes cluster has unavoidable trust relationships, but careful design can reduce their reach and limit the damage when a boundary fails.
There is no single switch that makes a Kubernetes cluster safe for mutually untrusted tenants. Hardening is a set of layered controls: reduce what tenants share, constrain the access they receive, and limit the blast radius when one control fails.
These techniques address different parts of that problem. Their value depends on your tenancy model, so start with the rights tenants hold and the degree of trust between them.