Instead of hard-coding specific information (such as node names or resource IDs) in a panel, Helm has several ways to create more dynamic and interactive dashboards:
filter panels
Template variables are available in metric queries and panel titles and appear as a drop-down list at the top of the dashboard. Select from the list to change the data the panel displays.
There are two queries you can customize:
specific node(s): nodeFilter(NODEFILTERSTRING)
specific resource(s) on a node: nodeResources(NODEID)
This procedure explains how to use variables in a query for a category of nodes (switches).
Select or create a panel. For this procedure, we created a panel that displays active TCP connections:
In the top right of the panel, click the dashboard settings icon and choose Variables>Add variable.
Specify the appropriate information, similar to the following. A preview of the values returned appears at the bottom of the screen:
Supported queries are in the form nodeFilter($filter) or nodeResource(FS:FID) where $filter is any filter expression.
In this case, we used the nodeFilter variable to specify the nodes in the category "switches".
Click Add.
Click Save.
After creating the template variable, you need to update the panel to make sure data is available from all the nodes rather than a specific one, as originally configured.
In the panel, type $node in the Node field.
Update the label to make it unique by typing the following: nodeToLabel($node).
A label must be unique to display data in the panel.
Save your dashboard.
Click the Node drop-down you created to select the nodes whose data you want to display:
