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MetricsHub Community Connectors 1.0.22

Detection by JMX

When to Use

Use jmx when connector eligibility is tied to a specific MBean/object name and attribute set. Typical usage: Java middleware and databases exposing JMX (for example Cassandra).

Syntax

connector:
  detection:
    criteria:
    - type: jmx
      objectName: org.apache.cassandra.metrics:type=Storage,name=Load
      attributes:
      - Count
      expectedResult: ^[0-9]

Properties

Property Required Default Description
type Yes - jmx.
objectName Yes - MBean object name/pattern to query. Must be non-blank.
attributes Yes - List of attributes read from the MBean.
expectedResult No none Regex matched against serialized JMX result.
errorMessage No none Connector-authored failure context (for logs/reporting).
forceSerialization No false Guarantees operations are performed sequentially against one host.

Runtime Behavior

JMX query results are treated as a table (List<Map<String,String>>) and serialized as =-separated name-value pairs before matching.

  • No expectedResult: success if serialized result is non-empty.
  • With expectedResult: case-insensitive regex match.

See below example on how a JMX result is converted to text before matching with expectedResult:

Criterion

Criterion

- type: jmx
  objectName: org.apache.cassandra.metrics:type=Storage,name=Load
  attributes:
  - Count
  - Unit
  expectedResult: Count=[0-9]+
Result

Result

Count Unit
123456 bytes
Result As Text

Result As Text

Count=123456
Unit=bytes

✅ The criterion passes because the serialized text contains a line that matches expectedResult: Count=[0-9]+.
  • Query one deterministic MBean for detection.
  • Request only required attributes.
  • Match stable numeric or enum-like values rather than free text.

Common Mistakes

  • Using too many attributes in detection when one is enough.
  • Matching volatile values (timestamps, counters with changing format).
  • Confusing detection criteria with data collection monitors.

Examples

Community example — the jmx criterion of Cassandra[1], included directly from the connector source:

- type: jmx
  objectName: org.apache.cassandra.metrics:type=Storage,name=Load
  attributes:
  - Count
  expectedResult: ^[0-9]
detection jmx mbean metricshub community connector hardware system
Links:
  • [1] https://github.com/metricshub/community-connectors/blob/main/src/main/connector/database/Cassandra/Cassandra.yaml
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