title: Use grafana variable dependency from other variable selection (with prometheus)
body: <p>I'm using Grafana to show Prometheus metrics. I have two variables in grafana, one is querying a <code>label_values(kubernetes_name)</code>.</p>
  <p>I want to create another variable which will provide <em><strong>instance</strong></em> label values, but I do not want to get all the values of this <em><strong>instance</strong></em> label, I want only those which came from a metrics that has kubernetes_name=$kubernetes_name where $kubernetes_name is coming from the first variable.</p>
  <p>Basically, I want to be able to run this label_values:</p>
  <pre><code>label_values(instance)
  </code></pre>
  <p>only if those came from a metrics which had label</p>
  <pre><code>kubernetes_name = $kubernetes_name
  </code></pre>
  <p>I'm not even sure I can do values dependency like this, I couldn't find it in the docs :/</p>