As part of the migration from OSSM 2 to OSSM 3, customers may decide that they need fewer control planes in OSSM 3 than they had in OSSM 2. This may be because OSSM 2 encouraged the creation of multiple control planes with its "multi-tenant" mode. We have spoken to some customers who, after further consideration of Istio's isolation features, which we plan to document with OSSM-8271, decide they do not need multiple control planes. 

Thus, they may want to migrate two or more OSSM 2 control planes (SMCPs) to a single control plane (Istio) in OSSM 3 while minimizing disruption to the workloads. Thus, we should test how this can be done and what the impacts to the workloads will be. 

Deliverable:

• A documented procedure for migrating workloads between 2 SMCPs in OSSM 2 and a single OSSM 3 (Istio) instance. Note the impact on the workloads - in particular, how to minimize downtime (if necessary). This can be captured in the openshift-service-mesh docs repo, and (for now) will not be published in the product documentation.
• (optional) use the docs-test mechanism to automatically test it