Populate dashboard variable from 2 queries?

Grafana Dashboards
1

  • What Grafana version and what operating system are you using?
    Grafana Cloud with Prometheus and Infinity data sources

  • What are you trying to achieve?
    Is there a way to have a dashboard query variable that’s populated by the combination of 2 queries?

  • How are you trying to achieve it?
    These metrics are all labeled with their hostname in the instance label. I use 2 dashboard query variables for site and instance. The first is a query to Netbox (using Infinity GraphQL) to get a list of sites. The second is another Netbox query getting a list of hostnames in the chosen site. This works great as a general pattern.
    But I have a few instances which are not yet documented in Netbox, and I’d like to see those on the same dashboard too, with unknown site. So I add another variable that queries a list of instance labels from the node_exporter_build_info metric.
    Now I’m looking for a way to join these 2 query variables into one big list.

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2

You can define joined variable like in the example below, but it will be populated with all values only when all values of var1 and var2 are selected:

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3

Thanks, that’s a clever idea. That does work but it’s pretty clunky to use. I don’t really know how else it could work though… maybe it’s best to make 2 separate dashboards for this.

4

Look at the new SQL expression datasource that you can use to marry two disparate data sources