Adding and Modifying Dashboards¶

The template classes system¶

Scylla Monitoring templates use class attribute that can be added to any JSON object in a template file. The different classes are defined in a file.

The class system resembles CSS classes. It is hierarchical, so a class type definition can have a class attribute and it would inherit that class attributes, the inherit class can add or override inherited attributes.

In the template file, you can also add or override attributes.

Scylla Monitoring Stack generation script, uses the types.json file and a template file and creates a dashboard.

When generating dashboards, each class will be replaced by its definition.

For example row in the type.json defined

{
 "base_row": {
     "collapse": false,
     "editable": true
 },
 "row": {
     "class": "base_row",
     "height": "250px"
 }
 }

In a Template it will be used like

{
     "class": "row",
     "height": "150px",
     "panels": [
     ]

The output will be

{
     "class": "row",
     "collapse": false,
     "editable": true,
     "height": "150px",
     "panels": [

     ]
}

We can see that the template added the panels attribute and override the height attribute.

Panel example¶

Look at the following example that defines a row inside a dashboard with a graph panel for the available disk size.

{
     "class": "row",
     "panels": [
         {
             "class": "bytes_panel",
             "span": 3,
             "targets": [
                 {
                     "expr": "sum(node_filesystem_avail) by (instance)",
                     "intervalFactor": 1,
                     "legendFormat": "",
                     "metric": "",
                     "refId": "A",
                     "step": 1
                 }
             ],
             "title": "Available Disk Size"
         }
     ]
}

In the example we used the bytes_panel class that generate a graph with bytes as units (that would mean that your Y axis unit would adjust themselves to make the graph readable (i.e. GB, MB, bytes, etc’)

You can also see that we override the span attribute to set the panel size.

To get a grasp of the difference, take a look at the Grafana panel example and see how it looks originally.

Grafana Formats and Layouts¶

Grafana layout used to be based on rows, each contains multiple panels. Each row would have a total span of 12, if the total span of the panels be larger than 12, it would break the lines into multiple lines.

Starting from Grafana version 5.0 and later, rows are no longer supported, it was replaced with a layout that uses absolute positions (ie. X,Y, height, width).

The server should be backward compatible, but we’ve found it had issues with parsing it correctly. More so, absolute positions are impossible to get right when done by hand.

To overcome these issues, the dashboard generation script will generate the dashboards in the Grafana version 5.0 format. In the transition, rows will be replaced with a calculated absolute position.

Panels height will be taken from their row. The span attribute is stil supported like you expect it to work, so does row height.

you can use the gridPos attribute which is a Grafana 5.0 format, but not like Grafana, you can use partial attributes.

gridPos has the following attributes:

{
   "x": 0,
   "y": 0,
   "w": 24,
   "h": 4
 }

When using Scylla’s template you don’t need to supply them all, so for example to specify that a row is 2 units height you can use:

{
   "gridPos": {
      "h": 2
    }
}

Generating the dashboards from templates (generate-dashboards.sh)¶

Validation¶

After making changes to a template, run the generate_generate-dashboards.sh you should see that it run without any errors.

Refresh your browser for changes to take effect. Make sure that your panels contain data, if not, maybe there is something wrong with your expr attribute.