envoyproxy/envoy

Tracing: upstream_cluster attribute missing when backend has no healthy replicas

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#25,887 opened on Mar 2, 2023

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area/routerenhancementhelp wanted

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Description

Title: Tracing: upstream_cluster attribute missing when backend has no healthy replicas

Description:

Given an envoy cluster of "foo_cluster" with some number of backends that is addressed via a k8s service name "foo-service".

If "foo_cluster" doesn't have any healthy backends (e.g. they are missing entirely, or maybe crash looping), spans generated by envoy on traffic that matches "foo_cluster" are missing the "upstream_cluster" attribute.

It would be helpful if "upstream_cluster" was always populated.

Contributor guide

Research direction
Investigate the span generation logic for upstream cluster attribute in Envoy's tracing code when the cluster has no healthy hosts. Trace the code path from the connection pool or router that populates the attribute and identify why it is omitted when no healthy backends exist.
Tech stack
cpp
Domain
backendapi
Issue type
Bug
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.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
C++EnvoyTracing
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50