Prometheus Scrape timeout

What is Prometheus Scrape timeout

Understanding Prometheus and Its Purpose

Prometheus is an open-source systems monitoring and alerting toolkit originally built at SoundCloud. It is designed to record real-time metrics in a time-series database, built using a highly dimensional data model. Prometheus is known for its powerful query language, PromQL, and is widely used for monitoring microservices and cloud-native environments.

Identifying the Symptom: Scrape Timeout

One common issue users encounter with Prometheus is the 'Scrape timeout' error. This symptom is observed when Prometheus fails to collect metrics from a target within the specified time limit. This can lead to gaps in data and potentially missed alerts if not addressed promptly.

Exploring the Issue: What Causes Scrape Timeout?

The 'Scrape timeout' error typically occurs when the scrape interval is too short or the target is slow to respond. Prometheus attempts to scrape metrics from targets at regular intervals, and if a target takes longer to respond than the configured timeout, the scrape will fail. This can be due to network latency, high load on the target, or inefficient target configuration.

Scrape Interval and Timeout Configuration

In Prometheus, the scrape interval and timeout are configured in the prometheus.yml file. The default scrape interval is 15 seconds, and the default timeout is 10 seconds. If the target cannot respond within this timeframe, a timeout error will occur.

Steps to Resolve Scrape Timeout Issues

To resolve scrape timeout issues, you can take several steps to either increase the timeout or optimize the target's response time.

Step 1: Increase the Scrape Timeout

One straightforward solution is to increase the scrape timeout in the prometheus.yml configuration file. This can be done by adjusting the scrape_timeout parameter for the affected job:

scrape_configs: - job_name: 'example' scrape_interval: 15s scrape_timeout: 20s static_configs: - targets: ['localhost:9090']

After making changes, restart Prometheus to apply the new configuration.

Step 2: Optimize Target Response Time

If increasing the timeout is not desirable, consider optimizing the target's response time. This may involve:

Reducing the amount of data the target needs to process and return. Improving the performance of the target application or server. Ensuring network connectivity is stable and has low latency.

Step 3: Monitor and Adjust

Continuously monitor the performance of your targets and adjust the scrape interval and timeout as necessary. Use Prometheus's built-in metrics and alerts to identify when targets are underperforming.

Additional Resources

For more detailed information on configuring Prometheus, refer to the official Prometheus configuration documentation. Additionally, the Prometheus overview provides a comprehensive introduction to its features and capabilities.