Proposal

Serverless currently offer two types of ServiceMesh support: with Kourier and without Kourier(net-istio), which stems from historical reasons[1].
I suggest that we discontinue support for ServiceMesh with Kourier[2], based on the following reasons:

• The statement "Use net-kourier when you don't require ServiceMesh, and opt for net-istio when ServiceMesh is needed" is quite straightforward.
• The usage and documentation are overly complex for users.
• Some features, such as SRVCOM-2648, cannot be supported by ServiceMesh with Kourier.

Concern

With that said, there are two points of concern:

• 1) Users cannot have a feature of authentication on Kourier.
• 2) Users cannot use Serverless in "multiple mesh".

For 1), we can recommend users to opt for ServiceMesh without Kourier (net-istio). Concerning the 2), while we currently lack a migration path, it's worth considering whether there are any customers who actually utilize Serverless in a multiple mesh configuration.
 
Deprecation Plan

1.  Inform about the deprecation in the 1.31 release note.
2.  If no feedback is received, proceed to remove the feature from the documentation in +3 minor version.
3.  Remove of test code from our repository also in version +3 minor version.

[1] The Evolution of our Ingress Support:

1. Initially, Kourier was utilized as our Ingress solution.
2. Some customers expressed interest in integrating Kourier with ServiceMesh, particularly for JWT token auth.
3. To meet this demand, we extended support for ServiceMesh integration with Kourier, as indicated in SRVLS-191.
4. Subsequently, a customer requested ServiceMesh mTLS capabilities.
5. In response, we reinstated support for ServiceMesh (net-istio) without Kourier, initially focusing exclusively on mTLS.
6. The application of ServiceMesh w/o Kourier was subsequently broadened to include various use cases, including MT and OpenShift AI, among others.

[2] 1.5. Integrating Service Mesh with OpenShift Serverless when Kourier is enabled