I'm trying to update my Spring Boot Application from 2.1.5.RELEASE to 2.2.5.RELEASE but my Tomcat metrics from Spring Boot Actuator start missing. When I reverted to 2.1.5.RELEASE they show up again. (http://localhost:8080/actuator/metrics metrics from actuator are usually here)
The exact metrics that are missing are:
tomcat.threads.busy
tomcat.threads.config.max
tomcat.threads.current
I'm afraid that there will be more missing metrics too. After I debug the problem I saw that MBeanExporter.afterSingletonsInstantiated is not call on application initialization which leads to not registered/exposed JMX beans and so later when TomcatMetrics.bindTo method is called TomcatMetrics.registerThreadPoolMetrics can't find those JMX beans needed for the metrics and they are not reported via spring-boot-actuator. (TomcatMetrics is class comming from spring-boot-actuator > io.micrometer > package io.micrometer.core.instrument.binder.tomcat )
I tested the same case in the same code base with 2.1.5.RELEASE and everything is working fine there. If you need more details message me :)
Comment From: snicoll
@gstaykov thanks for the report, this is covered in the release notes.
Comment From: gstaykov
ahhh .... I missed this :( Thank you !