feat(hadoop): Enable boolean metrics

[siegfriedweber]

Description

Allow boolean metrics to be exported for HDFS.

If a value field is provided in the JMX exporter rules, then the value is parsed as Double (see https://github.com/prometheus/jmx_exporter/blob/1.2.0/collector/src/main/java/io/prometheus/jmx/JmxCollector.java#L699-L714).
If the value field is "not specified the scraped mBean value will be used." (see http://prometheus.github.io/jmx_exporter/1.2.0/http-mode/rules/). This seems to be the usual case anyway.

If the bean value is used, numbers and booleans are supported (see https://github.com/prometheus/jmx_exporter/blob/1.2.0/collector/src/main/java/io/prometheus/jmx/JmxCollector.java#L800-L811).

With this change, e.g. the metric hadoop_namenode_security_enabled is exported:

# HELP hadoop_namenode_security_enabled Hadoop:name=NameNodeStatus,type=null,attribute=SecurityEnabled
# TYPE hadoop_namenode_security_enabled gauge
hadoop_namenode_security_enabled{kind="NameNodeStatus",role="NameNode",service="HDFS"} 0.0

Note

This pull request is just the byproduct of a research task for a customer. Instead of documenting the issue, I just fixed it.

Definition of Done Checklist

Please make sure all these things are done and tick the boxes

• Add an entry to the CHANGELOG.md file
• Integration tests ran successfully (test(smoke): Test boolean metrics hdfs-operator#690)

TIP: Running integration tests with a new product image

The image can be built and uploaded to the kind cluster with the following commands:

bake --product <product> --image-version <stackable-image-version>
kind load docker-image <image-tagged-with-the-major-version> --name=<name-of-your-test-cluster>

See the output of bake to retrieve the image tag for <image-tagged-with-the-major-version>.

[dervoeti]

Built and tested with stackabletech/hdfs-operator#690, changes look good.

[siegfriedweber]

Release notes

• HDFS: Boolean metrics like hadoop_namenode_security_enabled are exported.