envoyproxy/envoy

Custom clusters do not support endpoint discovery through EDS

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#15,663 opened on Mar 25, 2021

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enhancementhelp wanted

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Description

Title: Custom clusters do not support endpoint discovery through EDS

Description: Usage of eds_cluster_config is restricted to clusters that have type explicitly set to EDS. Envoy also uses this type for determining whether clusters are initialized during the primary or secondary phase, meaning it is not possible to write a custom cluster type that performs endpoint discovery via EDS.

Instead, I think the custom cluster type should specify whether it utilizes EDS for endpoint discovery, and if so, Envoy should treat it the same way as it does the native EDS cluster (i.e. the cluster is permitted to use eds_cluster_config, it is initialized during secondary phase if the config source is not file-based, etc.).

Contributor guide

Research direction
Understand how Envoy initializes clusters and handles EDS config. Then modify the custom cluster interface to allow specifying EDS usage, enabling EDS based endpoint discovery for custom clusters.
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.
1-2 days
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++
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40