Syntax: JMX Metrics Definitions
To write JMX metrics definitions, you need to know which JMX beans you want to collect, understand how the beans are structured, and know the required YAML elements. We recommend that you study the examples and use them as models for your JMX metrics definitions.
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About JMX Beans
To configure extended JMX bean definitions, it’s useful to understand the structure of a JMX bean as it appears in HTTP.
A JMX bean always has a name attribute, which contains the
domain and a set of
properties (for example, type and name).
The other attributes can have string, numeric, or composite values, and can essentially function as tags.
Composite values can be nested, and there is often a concept of an array of key-value pairs.
Consider the following example bean:
In this example, the name attribute’s
domain is “java.lang”.
CollectionUsageThresholdCount attribute is a numeric value;
Usage attribute is a composite value;
tag.hostName attribute functions as a tag.
The following example bean has nested composite values and arrays of key-value pairs:
About JMX Metrics Definitions
You can define multiple metrics for any given bean. Depending on the specified patterns, a given metric might translate into multiple metrics. You can control whether a metric is shown in your Pepperdata dashboard.
Generally, you define an extended JMX metric by its path of elements that precede it in its tree structure.
For example, the
committed attribute under the
Compressed Class Space key could be addressed by
LastGcInfo.memoryUsageAfterGc.Compressed Class Space.committed.
To specify which JMX beans’ metrics that you want Pepperdata to collect, you add JMX metrics definitions to your rules file. The PepAgent evaluates matching rules against all JMX, and if a bean matches a JMX metrics definition, PepAgent collects the bean’s data. The matching evaluation looks at the bean name, the matched groups in the metric name, and other attributes within the bean that are used to generate the tags and final metric name.
Example: Annotated JMX Metric Definition
This example shows a typical JMX metric definition. The
jmx list is a top-level dictionary—he same level as the
programs dictionary for custom program matching rules.
The names of the JMX services, such as “datanode”, are arbitrary labels for the service.
The table describes options for generating names and tags. Use brackets around tag names if they are followed by non-tag text.
|Replaced with matched groups in the “metric” pattern
|Replaced with corresponding property in the bean name
|Replaced with the attribute value of this name (if found)
YAML Sections: JMX Metrics Definitions
The tables describe the YAML sections for JMX metrics definitions. Unless labeled optional, keys are required.
Table: YAML Sections for JMX Metrics Definitions
|URI of JMX service. Can be an HTTP service (for example,
http://localhost:50075/jmx) or an RMI service (for example,
|List of beans with metrics to collect
|Name of bean (a regex pattern in Java regex syntax )
|List of metrics to collect within a matched bean
|Pattern to match on a metric. The groups that are matched may be referred to when generating tags or names.
|Name of the metric to generate. It can refer to matches from the metric pattern, properties, and other attributes in the bean (see below). The name is always lowercase and has spaces replaced with underscores. If not specified, a name is created based on the domain, the “type” and “service” properties, and the path to the attribute name.
|Information about how to display the metric; see Table: YAML Sections for ‘display’ Dictionary, below.
|Map of tags to generate. The tag values can refer to matches from the metric pattern, properties, and other attributes in the bean (see below). The canonical hostname is always added as the “host” tag, and any “host” tag specified in the configuration is ignored.
Table: YAML Sections for display Dictionary
|(Default is the metric name) User-visible description of the metric.
|(Default is calculated) Maximum y-value of the metric.
|(Default is 1) Scaling factor of the metric (a number).
|(Default=GAUGE) Metric type: COUNTER or GAUGE.
|User-visible units of the metric; for example, “GB”, “MBps”.
Example: HBase Regionserver
HBase has very complex names for its regionserver metrics. The bean looks similar to the following:
The following JMX metrics definition enables Pepperdata to collect tagged metrics from the example bean:
Example: Kafka RMI Interface
The following metrics definitions provide Kafka metrics that are exposed via RMI (Remote Method Invocation):