Istio side car blocking max connection


We are running istio 1.3 and found that on increasing thread greater than 1024 of our application we are getting performance block. As even if we tune our application to 2000 concurrent thread, still pod running on istio connect 1024 at a time, due to which we are facing performanc edegradation.

So want to check is there some properties through which we can increase the max concurrent connection limit for our side cars?

I installed istio 1.3 using helm chart :; with default values.yaml

1.3 puts many limits on the connection/request pools:
1.4 I believe dropped those limits, but you can change them with a destination rule in 1.3 I believe.

Are you getting 503 reset connection before headers? We have Istio 1.4.3 and we experience those from time to time via Gateways.

We are not using Gateway, but in 1.3 getting 503 for producer service, as producer service is running from more than 3000 threads and tried to connect to consumer.

@kuat will check with destination rule may be that will help.