envoyproxy/envoy

reduce health check rate if there is active succeeding traffic

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#9,351 opened on Dec 13, 2019

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area/perfarea/service discoveryhelp wanted

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Description

This came up from a conversation I think with @snowp at KubeCon/EnvoyCon: we should be able to optionally lower the active health check rate if we are receiving a sufficient amount of passive traffic. As long as the upstream is able to send x-envoy-immediate-health-check-fail (as an upstream Envoy would do), draining should still be possible even in the passive case.

This would potentially mitigate some HC traffic explosion without having to resort to centralized HC.

Contributor guide

Research direction
Examine the existing health check implementation in Envoy, understand how active and passive health checking work, and propose a design to reduce the active check rate when passive traffic indicates success.
Tech stack
cpp
Domain
backendinfrastructure
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
C++Envoy
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50