PrometheusTargetScrapeDuplicate

PrometheusTargetScrapeDuplicate #

Prometheus has many samples rejected due to duplicate timestamps but different values

Alert Rule
alert: PrometheusTargetScrapeDuplicate
annotations:
  description: |-
    Prometheus has many samples rejected due to duplicate timestamps but different values
      VALUE = {{ $value }}
      LABELS = {{ $labels }}    
  runbook: https://srerun.github.io/prometheus-alerts/runbooks/prometheus-self-monitoring-internal/prometheustargetscrapeduplicate/
  summary: Prometheus target scrape duplicate (instance {{ $labels.instance }})
expr: increase(prometheus_target_scrapes_sample_duplicate_timestamp_total[5m]) > 0
for: 0m
labels:
  severity: warning

Here is a sample runbook for the PrometheusTargetScrapeDuplicate alert:

Meaning #

The PrometheusTargetScrapeDuplicate alert is triggered when Prometheus detects duplicate timestamps with different values in its scrape samples. This means that Prometheus has received multiple samples with the same timestamp but different values, which can lead to inconsistent and inaccurate metric data.

Impact #

This alert can have a significant impact on the accuracy and reliability of Prometheus metrics. Duplicate samples can lead to:

  • Inconsistent metric data
  • Incorrect alerting and notification
  • Inaccurate monitoring and visualization
  • Degraded performance and increased latency

Diagnosis #

To diagnose the issue, follow these steps:

  1. Check the Prometheus logs for any errors or warnings related to duplicate samples.
  2. Verify that the scrape configuration is correct and that there are no duplicate scrape targets.
  3. Check the metric data for any anomalies or inconsistencies.
  4. Verify that the timestamp format and timezone settings are correct.
  5. Check for any network or connectivity issues that may be causing duplicate samples.

Mitigation #

To mitigate the issue, follow these steps:

  1. Review and update the scrape configuration to ensure that there are no duplicate scrape targets.
  2. Verify that the timestamp format and timezone settings are correct.
  3. Implement deduplication mechanisms in the scrape pipeline to remove duplicate samples.
  4. Increase the scrape interval to reduce the likelihood of duplicate samples.
  5. Consider implementing additional logging and monitoring to detect and alert on duplicate samples.

Note: The mitigation steps may vary depending on the specific use case and Prometheus configuration. This runbook is intended to provide general guidance and may need to be tailored to the specific environment and requirements.