As of today no route found and route is found but the cluster in that route is not ready are sharing the same error detail.
However, this make big difference. The latter is likely a RDS config problem, or explicit blackhole.
The latter might be a slow CDS.
Address #15448
Signed-off-by: Yuchen Dai <silentdai@gmail.com>
Mirrored from https://github.com/envoyproxy/envoy @ a11d48368c62eb2c238d6d3087c16ffa355243d1