Скачать или смотреть How to Retrieve Multi Lines from Multi-Select Variables in Grafana

Discover how to effectively use multi-select variables in Grafana to display multiple lines from a single query with PromQL.
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This video is based on the question https://stackoverflow.com/q/76258229/ asked by the user 'Christian Bongiorno' ( https://stackoverflow.com/u/889053/ ) and on the answer https://stackoverflow.com/a/76259848/ provided by the user 'markalex' ( https://stackoverflow.com/u/21363224/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Mastering Grafana: Extracting Multi Lines Using Multi-Select Variables

Grafana is an incredibly powerful tool for visualizing time series data, but sometimes it can feel challenging to tailor queries to get the precise data you need. A common issue arises when users want to retrieve multi-lines from a multi-select variable in a Prometheus query. In this guide, we’ll break down how to achieve this and fine-tune your Grafana dashboards.

The Problem: Multi-Select Variables in Grafana

Imagine you have a situation where you want to display several metrics for a specific pod within Grafana, and you have one variable set up as multi-select. Here’s a quick overview of your setup:

You have two variables: METRIC (multi-select) and POD (single select).

Your goal is to display multiple lines of metrics (say 4 metrics) for a single selected pod.

This situation may seem confusing at first, especially if you're new to using PromQL with Grafana. So how can you address this requirement effectively?

The Solution: Using Regex Selector in PromQL

Whenever you encounter a multi-select variable in Grafana, the key to your solution lies in leveraging the regex selector =~. This allows you to match multiple values dynamically within your queries.

Step-by-Step Breakdown:

Understanding Variable Substitution:
In Grafana, when you use a multi-select variable like $METRIC, Grafana will automatically replace that variable with a regex format during the query execution. For instance, if you select three metrics, it would be substituted as (val1|val2|val3).

Modifying Your Query:
Using the information above, you can modify your original query to incorporate the regex selector. Your original query was:

[[See Video to Reveal this Text or Code Snippet]]

To accommodate the regex for the multi-select variable, you should adjust your query to:

[[See Video to Reveal this Text or Code Snippet]]

Execute and Visualize:
Once you've updated your query, execute it within Grafana. You should now see individual lines corresponding to each metric selected in the multi-select dropdown for the specified pod.

Tips for Optimizing Grafana Queries

Test your Queries: Always test your PromQL queries in the InfluxDB or Prometheus interface first before putting them into Grafana.

Use Variables Wisely: Ensure your multi-select variables are well-defined so that the data they fetch remains relevant to your queries.

Dashboard Performance: Monitor the performance and response time of your dashboards, especially when dealing with multiple metrics to fine-tune for quicker loading times.

Conclusion

By utilizing the regex selector in your Grafana queries, you can easily extract multi lines from multi-select variables and bring rich, real-time data visualization to your dashboard. Whether you're a seasoned user or a newcomer to Grafana, understanding the nuances of variable handling will help you create more dynamic and informative visualizations. Enjoy customizing your Grafana dashboards!