ThreeMammals/Ocelot

How to avoid calling down service in load balancer option

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#1,041 opened on Oct 17, 2019

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Health CheckLoad BalancerQoSacceptedbughelp wantedhighmedium effort

Description

Expected Behavior / New Feature

Load balancer should able to recognize the down service and stop calling service or up the service.

Actual Behavior / Motivation for New Feature

Load balancer is calling the service although the service is down and returning 500 internal server on every call.

Steps to Reproduce the Problem

  1. Created two instance of the same module and run on different port.
  2. Added load balance option for those two service instance of type RoundRobin.
  3. Kill the second service and now Ocelot still redirect to down service.

Specifications

  • Version: 13.5.2
  • Platform: Windows 10
  • Subsystem:

Contributor guide

Tech stack
csharp
Domain
backendapiperformance
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.
needs maintainer response
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
needs investigation
Prerequisites
C#load balancing concepts
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
This feature request asks the Ocelot API Gateway to avoid routing to a down service. The solution likely involves implementing health checks that periodically probe backends and update the load balancer's state. Begin by examining the existing load balancer implementation in Ocelot, particularly the RoundRobin class and how it selects downstream services. Then review any existing health check middleware or discuss with maintainers on the issue thread to clarify desired design (e.g., passive vs active health checks). Suggested files to investigate: src/Ocelot/LoadBalancer/LoadBalancers/ and related tests.
How to avoid calling down service in load balancer option · ThreeMammals/Ocelot#1041 | Good First Issue