Please see istio/istio#31825 and also you can see AWS is doing the "right" thing and defaulting it to 0 with the option to modify it in the rare case that a different behavior is desired: https://docs.aws.amazon.com/app-mesh/latest/userguide/envoy-config.html

Feature Description

We are running into a pretty unpleasant problem where Envoy sidecar reaches the default 15s initial_fetch_timeout and then continues with starting up and responding with LIVE to the /ready endpoint while it has NOT loaded all upstreams for all clusters from Consul.

We believe Consul should default initial_fetch_timeout to 0 because starting the Envoy proxy sidecar with incorrect configuration is much worse than not starting at all (which we can handle much easier)

Use Case(s)

Not having broken service mesh :)