prometheus/prometheus

Add cardinality_limit to scrape config

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#11,061 opened on Jul 25, 2022

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component/configcomponent/scrapinghelp wantedkind/featurepriority/P3

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Description

Proposal

In order to stop targets from overloading label values and also the metric __name__ index, add a scrape config limiter that limits the number of unique label values per scrape.

This will protect, for example:

  • When other metric systems are translated to Prometheus incorrectly and tag values become part of the metric name.
  • When a piece of data is not filtered and exposed as thousands of label values.

Contributor guide

Research direction
Investigate how to add a cardinality limit configuration parameter in the scrape config struct, implement logic to count unique label values per scrape target and enforce the limit, and add tests.
Tech stack
go
Domain
backenddevops
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.
Mostly clear
Prerequisites
GoPrometheus scrape configuration
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60