Due to the changes done to the micrometer subsystem with WFLY-19283 (at least) the undertow metrics related to the deployed application are missing.

Before, the collectMetrics method of the MicrometerCollector has been called several times during startup. Now it's only called once, way before the application is deployed. Thus the undertow metrics are not there yet and subsequently also missing from the export.

Here is a before-after comparison:

before

after

Supposedly this could affect other deployment-based metrics that are extracted from the subsystems as well.