A process for exposing JMX Beans via HTTP for Prometheus consumption
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Signed-off-by: Stavros Kontopoulos <stavros.kontopoulos@lightbend.com>
Latest commit 4eb95cd Sep 10, 2018

README.md

JMX Exporter

JMX to Prometheus exporter: a collector that can configurably scrape and expose mBeans of a JMX target.

This exporter is intended to be run as a Java Agent, exposing a HTTP server and serving metrics of the local JVM. It can be also run as an independent HTTP server and scrape remote JMX targets, but this has various disadvantages, such as being harder to configure and being unable to expose process metrics (e.g., memory and CPU usage). Running the exporter as a Java Agent is thus strongly encouraged.

Running

To run as a javaagent download the jar and run:

java -javaagent:./jmx_prometheus_javaagent-0.3.1.jar=8080:config.yaml -jar yourJar.jar

Metrics will now be accessible at http://localhost:8080/metrics

To bind the java agent to a specific IP change the port number to host:port.

See ./run_sample_httpserver.sh for a sample script that runs the httpserver against itself.

Building

mvn package to build.

Configuration

The configuration is in YAML. An example with all possible options:

---
startDelaySeconds: 0
hostPort: 127.0.0.1:1234
username: 
password: 
jmxUrl: service:jmx:rmi:///jndi/rmi://127.0.0.1:1234/jmxrmi
ssl: false
lowercaseOutputName: false
lowercaseOutputLabelNames: false
whitelistObjectNames: ["org.apache.cassandra.metrics:*"]
blacklistObjectNames: ["org.apache.cassandra.metrics:type=ColumnFamily,*"]
rules:
  - pattern: 'org.apache.cassandra.metrics<type=(\w+), name=(\w+)><>Value: (\d+)'
    name: cassandra_$1_$2
    value: $3
    valueFactor: 0.001
    labels: {}
    help: "Cassandra metric $1 $2"
    type: GAUGE
    attrNameSnakeCase: false
Name Description
startDelaySeconds start delay before serving requests. Any requests within the delay period will result in an empty metrics set.
hostPort The host and port to connect to via remote JMX. If neither this nor jmxUrl is specified, will talk to the local JVM.
username The username to be used in remote JMX password authentication.
password The password to be used in remote JMX password authentication.
jmxUrl A full JMX URL to connect to. Should not be specified if hostPort is.
ssl Whether JMX connection should be done over SSL. To configure certificates you have to set following system properties:
-Djavax.net.ssl.keyStore=/home/user/.keystore
-Djavax.net.ssl.keyStorePassword=changeit
-Djavax.net.ssl.trustStore=/home/user/.truststore
-Djavax.net.ssl.trustStorePassword=changeit
lowercaseOutputName Lowercase the output metric name. Applies to default format and name. Defaults to false.
lowercaseOutputLabelNames Lowercase the output metric label names. Applies to default format and labels. Defaults to false.
whitelistObjectNames A list of ObjectNames to query. Defaults to all mBeans.
blacklistObjectNames A list of ObjectNames to not query. Takes precedence over whitelistObjectNames. Defaults to none.
rules A list of rules to apply in order, processing stops at the first matching rule. Attributes that aren't matched aren't collected. If not specified, defaults to collecting everything in the default format.
pattern Regex pattern to match against each bean attribute. The pattern is not anchored. Capture groups can be used in other options. Defaults to matching everything.
attrNameSnakeCase Converts the attribute name to snake case. This is seen in the names matched by the pattern and the default format. For example, anAttrName to an_attr_name. Defaults to false.
name The metric name to set. Capture groups from the pattern can be used. If not specified, the default format will be used. If it evaluates to empty, processing of this attribute stops with no output.
value Value for the metric. Static values and capture groups from the pattern can be used. If not specified the scraped mBean value will be used.
valueFactor Optional number that value (or the scraped mBean value if value is not specified) is multiplied by, mainly used to convert mBean values from milliseconds to seconds.
labels A map of label name to label value pairs. Capture groups from pattern can be used in each. name must be set to use this. Empty names and values are ignored. If not specified and the default format is not being used, no labels are set.
help Help text for the metric. Capture groups from pattern can be used. name must be set to use this. Defaults to the mBean attribute decription and the full name of the attribute.
type The type of the metric, can be GAUGE, COUNTER or UNTYPED. name must be set to use this. Defaults to UNTYPED.

Metric names and label names are sanitized. All characters other than [a-zA-Z0-9:_] are replaced with underscores, and adjacent underscores are collapsed. There's no limitations on label values or the help text.

A minimal config is {}, which will connect to the local JVM and collect everything in the default format. Note that the scraper always processes all mBeans, even if they're not exported.

Example configurations for javaagents can be found at https://github.com/prometheus/jmx_exporter/tree/master/example_configs

Pattern input

The format of the input matches against the pattern is

domain<beanpropertyName1=beanPropertyValue1, beanpropertyName2=beanPropertyValue2, ...><key1, key2, ...>attrName: value
Part Description
domain Bean name. This is the part before the colon in the JMX object name.
beanProperyName/Value Bean properties. These are the key/values after the colon in the JMX object name.
keyN If composite or tabular data is encountered, the name of the attribute is added to this list.
attrName The name of the attribute. For tabular data, this will be the name of the column. If attrNameSnakeCase is set, this will be converted to snake case.
value The value of the attribute.

No escaping or other changes are made to these values, with the exception of if attrNameSnakeCase is set. The default help includes this string, except for the value.

Default format

The default format will transform beans in a way that should produce sane metrics in most cases. It is

domain_beanPropertyValue1_key1_key2_...keyN_attrName{beanpropertyName2="beanPropertyValue2", ...}: value

If a given part isn't set, it'll be excluded.

Testing

mvn test to test.

Debugging

You can start the jmx's scraper in standalone mode in order to debug what is called

java -cp jmx_exporter.jar io.prometheus.jmx.JmxScraper service:jmx:rmi:your_url

To get finer logs (including the duration of each jmx call), create a file called logging.properties with this content:

handlers=java.util.logging.ConsoleHandler
java.util.logging.ConsoleHandler.level=ALL
io.prometheus.jmx.level=ALL
io.prometheus.jmx.shaded.io.prometheus.jmx.level=ALL

Add the following flag to your Java invocation:

-Djava.util.logging.config.file=/path/to/logging.properties

Installing

A Debian binary package is created as part of the build process and it can be used to install an executable into /usr/bin/jmx_exporter with configuration in /etc/jmx_exporter/jmx_exporter.yaml.