What will happen to web socket connections when envoy reload new envoyfilters (hot restart ) about envoy HOT 4 OPEN

Here is another example, another traffic request jumped too

from envoy.

Oh, the requests might not be doubled. It's websocket connection got terminated and reconnected, looks like this is expected when I update the filter above(listener replace will cause client reconnect).
Would be appreciate if someone can share some insights under the hood and will it helpful if I configure drain time for this , thanks!

from envoy.

I'm not certain what kind of update happens in your case, but in general:

• If a listener (LDS) is updated - the old listener will be drained (see docs, and this) and a new one will be created to serve the new connections.
• If you just need to update the filters (and not the listener), you may be able to use ECDS - this will avoid draining the listener, but will only impact new connections.

from envoy.

Thanks a lot for the info.
I did patched this to listener's filterChain, so should be an expected behavior from Envoy. Will also look at the doc links you shared. I think at least I have two things worth to try now:

1. Tune the drain time when envoy hotrestart, maybe can do some manual rollout for envoy pods while they draining.
2. Yeah, I will experiment patching this to extension using ECDS instead of LDS, see what I can get.

from envoy.