Envoy is slow to apply endpoints updates



I noticed that sometime the endpoints configuration of the envoy proxy running on a Pod takes minutes to be updated.

I could confirm that by deleting a Pod of an external service and comparing the result of curl -X GET http://localhost:15014/v1/registration (Pilot) and istioctl proxy-config endpoints myapp (Envoy).
The first command (Endpoints from Pilot) get the update instantly whereas the second (Endpoints from Proxy) takes sometime minutes to apply the changes.

Enabling the debug log on the Pilot helped me to find this but I’m not sure if it’s relevant:

istio-pilot-7bf698bc99-c4wxq discovery 2019-05-16T14:17:33.854384Z	info	ads	Push finished: 2.864784307s

I first thought that it was due to this bug but upgrading Istio from 1.1.2 to 1.1.6 didn’t solve the problem.

If anyone have an idea what I could check to identify more precisely the root cause, he’s welcome.

Thanks for your help.