Can we deprecate local-gateway.mesh: "mesh" in config-istio?

[nak3]

This is an Istio specific question but opening in serving repo for wide visibility.

TL;DR: Please let us know if anyone is using local-gateway.mesh: "mesh" and it will cause a trouble if we deprecate the configuration.

Background

When using net-istio with sidecar injection, we can configure local-gateway.mesh: "mesh" in config-istio:

    # To use only Istio service mesh and no knative-local-gateway, replace
    # all local-gateway.* entries by the following entry.    
    local-gateway.mesh: "mesh"

Once it was configured, cluster local traffic 100% relies on mesh. In other words, no-mesh to mesh traffic stops working.

Now, we are planning to deprecate the config with the following reasons:

• DomainMapping cannot enable local-gateway.mesh as discussed in DomainMapping does not work with local gateway "mesh" mode knative-extensions/net-istio#562 (comment)
• E2E test does(will) not enable local-gateway.mesh (because domainmapping tests fail and mesh specific option for test is necessary.)
• mesh to mesh traffic has no difference between w/ and w/o local-gateway.mesh. The option is just to use only mesh and completely remove local gateway.

[markusthoemmes]

An announcement on the knative-dev list might be worth thinking about.

[julz]

/triage accepted

FWIW I could see an argument for not deprecating this and instead documenting clearly the downsides and removing it from the main "installing with istio docs" (we could put it in an advanced section, "preventing access to Knative Services from outside the mesh" or something). Having said that I think if we ask Knative-dev (and -users?) and no-one wants it, or complains during the deprecation period, then fair enough.

[nak3]

Thank you for the advice. I started the ML thread in https://groups.google.com/g/knative-users/c/tU8-xKKZu5Q

[dprotaso]

@nak3 I'm assuming we can drop that config option now?

[nak3]

Thank you. Yes, we can. I sent knative-extensions/net-istio#915 .