Creating a New Chart¶
When you start with a new space you’ll see a placeholder for a chart with a large plus in it. To add charts to existing Spaces just click on the plus button in the menu bar.
As a next step you choose the chart type. If you can’t decide don’t worry, you can change it later.
After choosing the type of chart you’d like to create the chart editor will slide up from the bottom of the screen. The chart editor shows you a list of the metrics you’re currently emitting to our API. You can narrow down the list by typing a pattern into the search box. As soon as you start typing the list is filtered.
Adding Metrics to a Chart¶
Add one or more metrics to the chart by checking them, and clicking the Add Metrics to Chart button.
After adding metrics you can see a preview of your chart.
Adding Annotations to a Chart¶
Click on “Add More Metrics” to add more metrics or events. Click on the Metrics button and select Events instead of Metrics to add annotations to your chart.
When you are done adding metrics and events you can name the chart and save it to add it to your Space.
Sources and Summarization¶
Assuming data exists for the current time-interval displayed by the chart, you will typically see one line per metric displayed in the chart. Even if you are sending the CPU load metric for 100 servers, you will only see a single line for the CPU load metric because of the stream composition. If grouping / summarization is set to average of averages it means that the data point is computed by averaging across all sources and each source is averaged over time.
To see one line per sources for the metric, change the grouping function under grouping / summarization from Average to Breakout.
You can modify the source settings and stream composition (display as menu) for each metric individually using the pull-down menus to the right of each metric name, or by checking multiple metrics and clicking the Set (group | summary) function buttons.
The first summarization list selects how your metric data is summarized across Sources, while the second selects how your metric data is summarized across Time. For example, Max of the Maxes will draw a single line for all sources consisting of the maximum value, from the source returning the maximum value in each time interval, while Breakout of the Average will show a line per source which depicts the average of all the values returned by each source in each time interval.
The available options for summarizing across sources are:
- breakout (displays one line per sources)
Options for how you summarize each source across time (the x-axis) when you are sending a gauge type metric the options are:
- counts (this is the count of measurements in the period)
If you are sending a metric of type ‘counter’ we show the derivative.
Each metric has a number of attributes associated with it. One we like to highlight is y-axis association. By default the metrics you select will share the same y-axis. If you want to give a metric its own y-axis you can set that in the stream attributes. You can view and modify these attributes by selecting Attributes from the pull-down menu to the right of each metric.
The attributes you can edit are:
- Display Name: Metric name displayed by the tooltip.
- Color: Set the color of your metric either via hex code or the color picker (read more here).
- Units: Units label displayed by the tooltip.
- Transform: Apply a simple formula to the data to, for example,
convert between units like Fahrenheit to Celsius
((x-32)/1.8), or compute rates
(x/p). Permitted variables are
x(data point) and
p(period). Read more about display transforms.
- Show on Separate Axis: Check this to set a custom Y-axis label
for this metric.
- Label: Custom name for the y-axis. Every metric in a chart that shares the same y-axis name, shares the same y-axis. Conversely, each metric with a Unique y-axis name creates and uses it’s own y-axis in the chart.
- Minimum: Set the minimum value of the y-axis, e.g. if you only expect positive values you can set this to 0.
- Maximum: Set the maximum value of the y-axis, e.g. if you are tracking a percentage you can set this to 100.
- Metric reports every: Interval at which you are sending us data (otherwise knows as the period). We use this setting along with the Reports Infrequently setting to properly handle gap-detection for your data. If the period is set, gaps will show for periods where no data is received. If it is not set, data points will be connected. Read more in the API docs.
- Reports Infrequently: Some metrics are reported opportunistically i.e. every n seconds a measurement is sent only if there is new data. This results in a sparsely populated series. We use this setting in combination with the Period to correctly handle Gap-Detection.
Understanding the Y-axis label, Period, and Reports Infrequently settings are key to your happiness as a customer using Librato. We highly encourage you to read up on these settings and experiment with them until they are friendly and familiar.
When you hover over a chart, a tooltip appears that shows you values for each metric in the chart. In the tooltip, you can sort the metrics by size and name, and even filter the series based on a pattern.