Slow start Configuration Not Working as Expected

[ashishyadav-meesho]

Title: Slow start Configuration Not Working as Expected

Description:
Issue: We have configured slow start for some of our services but have observed two different behaviors across pods. While some pods are honoring the slow start as expected, others are taking significantly longer to ramp up to full capacity. It would be greatly appreciated if you could help identify whether this is due to a configuration issue or a potential issue with Envoy.

Repro steps:
Setup contour envoy as a deployment running three instances of contour and envoy as proxy, We are running contour version: 1.27.2 and envoy image is: docker.io/bitnami/envoy:1.27.2-debian-11-r1

Slow Start configuration:

Request Metrics:

[nezdolik]

@ashishyadav-meesho I will need more information to be able to debug:

1. please attach Envoy (not contour) config, you could get it from http://{$ENVOY_POD_IP}:{$ADMIN_PORT}/config_dump
2. output from clusters endpoint (that concerns this specific cluster), you could get it from http://{$ENVOY_POD_IP}:{$ADMIN_PORT}/clusters
3. was there any change of pod health status during the time when you experienced issue with slow start?