The multi control plane support in upstream Istio is still experimental. We need to move it to Alpha and ultimately to GA, because OSSM already fully supports multiple control planes in a single cluster.

Support for multiple Istio control planes in the same cluster is a critical migration path for customers currently running multiple meshes using OSSM 2.x. Today, users often deploy isolated control planes to achieve tenant or team separation, customized mesh behavior, or gradual upgrades. Upstream Istio lacks comprehensive support, documentation, and testing for this use case.

We propose enabling and standardizing multi-control plane support upstream, improving the experience across installation, discovery, routing, security, and testing. This feature also lays the foundation for future enhancements such as Ambient mesh compatibility and better inter-control plane communication using APIs like ReferenceGrant.

The goal is to move this feature to alpha in the near term, focusing on documentation, experimental support, and clear patterns for adoption.