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Scheduler Metrics

YuniKorn leverages Prometheus to record metrics. The metrics system keeps tracking of scheduler's critical execution paths, to reveal potential performance bottlenecks. Currently, there are three categories for these metrics:

  • scheduler: generic metrics of the scheduler, such as allocation latency, num of apps etc.
  • queue: each queue has its own metrics sub-system, tracking queue status.
  • event: record various changes of events in YuniKorn.

all metrics are declared in yunikorn namespace.

Scheduler Metrics

Metrics NameMetrics TypeDescription
containerAllocationCounterTotal number of attempts to allocate containers. State of the attempt includes allocated, rejected, error, released. Increase only.
applicationSubmissionCounterTotal number of application submissions. State of the attempt includes accepted and rejected. Increase only.
applicationGaugeTotal number of applications. State of the application includes running, completed and failed.
nodeGaugeTotal number of nodes. State of the node includes active and failed.
nodeResourceUsageGaugeTotal resource usage of node, by resource name.
schedulingLatencyHistogramLatency of the main scheduling routine, in milliseconds.
sortingLatencyHistogramLatency of all nodes sorting, in milliseconds.
tryNodeLatencyHistogramLatency of node condition checks for container allocations, such as placement constraints, in milliseconds.
tryPreemptionLatencyHistogramLatency of preemption condition checks for container allocations, in milliseconds.

Queue Metrics

Metrics NameMetrics TypeDescription
appMetricsGaugeQueue application metrics. State of the application includes running, accepted, rejected, failed, completed, allocated, released.
ResourceMetricsGaugeQueue resource metrics. State of the resource includes guaranteed, max, allocated, pending, preempting.

Event Metrics

Metrics NameMetrics TypeDescription
totalEventsCreatedGaugeTotal events created.
totalEventsChanneledGaugeTotal events channeled.
totalEventsNotChanneledGaugeTotal events not channeled.
totalEventsProcessedGaugeTotal events processed.
totalEventsStoredGaugeTotal events stored.
totalEventsNotStoredGaugeTotal events not stored.
totalEventsCollectedGaugeTotal events collected.

Access Metrics

YuniKorn metrics are collected through Prometheus client library, and exposed via scheduler restful service. Once started, they can be accessed via endpoint http://localhost:9080/ws/v1/metrics.

Aggregate Metrics to Prometheus

It's simple to setup a Prometheus server to grab YuniKorn metrics periodically. Follow these steps:

  • Setup Prometheus (read more from Prometheus docs)

  • Configure Prometheus rules: a sample configuration

scrape_interval: 3s
evaluation_interval: 15s

- job_name: 'yunikorn'
scrape_interval: 1s
metrics_path: '/ws/v1/metrics'
- targets: ['']
  • start Prometheus
docker pull prom/prometheus:latest
docker run -p 9090:9090 -v /path/to/prometheus.yml:/etc/prometheus/prometheus.yml prom/prometheus

Use instead of localhost if you are running Prometheus in a local docker container on Mac OS. Once started, open Prometheus web UI: http://localhost:9090/graph. You'll see all available metrics from YuniKorn scheduler.