Grafana: Dashboarding and Visualization

Grafana is an open-source platform for monitoring and observability. It allows you to query, visualize, alert on, and explore your metrics, logs, and traces no matter where they are stored. Grafana provides a powerful and elegant way to create interactive dashboards from various data sources, including Prometheus, Elasticsearch, InfluxDB, and many more.

Grafana Dashboard Tips

Customizing Panel Legends for Readability

When adding a panel to a dashboard, the default legend might display very long or uninformative metric names, especially when querying multiple series. To improve readability, you can customize the legend to show more relevant labels.

You can use template variables within the legend field to display specific labels from your metrics.

Example: If your metric has labels like instance and dimension, you can use:

{{instance}} - {{dimension}}

This will replace the full metric name with a more concise representation, making it easier to understand which line corresponds to which data series.

PromQL (Prometheus Query Language) Basics

PromQL is Prometheus’s functional query language, designed for flexible and powerful querying of time-series data. Grafana commonly uses PromQL when Prometheus is configured as a data source.

Filtering with Multiple Values (Regex Matching)

To filter metrics based on a label having one of several possible values, you can use the regular expression matching operator =~.

Example: To select metrics where the job label is either node-exporter or kube-state-metrics:

<metric_name>{job=~"node-exporter|kube-state-metrics"}

• =~: Selects labels that regex-match the provided string.
• |: Acts as an “OR” operator within the regex.

Other Common PromQL Functions and Operators

• rate(): Calculates the per-second average rate of increase of the time series over a time duration. Useful for counters.

  rate(http_requests_total[5m])

• sum(): Sums up vector elements over a label set. Often combined with by() or without() for aggregation.

  sum(node_cpu_seconds_total) by (instance)

• increase(): Calculates the increase in the time series over a time duration. Useful for counters that might reset.

  increase(node_network_transmit_bytes_total[1h])

Grafana Variables

Grafana variables allow you to create dynamic and interactive dashboards. Instead of hardcoding values in your queries, you can use variables that users can select from dropdowns.

Example: Creating a “datasource” variable You can create a variable named datasource that lists all available Prometheus instances. Then, in your panel queries, you can use ${datasource} in your PromQL queries to dynamically switch between data sources.

up{job="${job}"} # Example of using a variable named 'job' in a query

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Note: For more advanced PromQL queries and Grafana features, refer to the official Prometheus and Grafana documentation.