MicroProfile Metrics API returns no data for vendor:system_cpu_load PAYARA-4147

[sschellh]

Description

---

Since Payara Micro 5.193 the /metrics endpoint does not return data for the field vendor:system_cpu_load anymore. The value is always zero.

Expected Outcome

Calling GET {baseUrl}/metrics/vendor returns the field vendor:system_cpu_load with a value > 0.

Current Outcome

Calling GET {baseUrl}/metrics/vendor the field vendor:system_cpu_load is always zero.

Also the naming of the field changed.
Before 5.193 it is vendor:system_cpu_load
Since 5.193 it is vendor_system_cpu_load
(not that the : was replaced by _)

Steps to reproduce (Only for bug reports)

Execute java -jar payara-micro-5.193.jar --deploy anyApplication.war
Visit http://localhost:8080/metrics/vendor

Samples

Payara Micro 5.191
vendor:system_cpu_load 0.15454493453568963

Payara Micro 5.192
vendor:system_cpu_load 0.5629938578656155

Payara Micro 5.193
vendor_system_cpu_load 0

Environment

• Payara Version: 5.193
• Edition: Micro
• JDK Version: Oracle Jdk, OpenJdk (Version 1.8)
• Operating System: Windows, Linux

[khasunuma]

I reproduced it. The data source that is "java.lang:type=OperatingSystem/SystemCpuLoad" in MBean indicates correct value, so it's certainly a bug. I reported it as an internal issue (PAYARA-4147).

Note that Payara Micro 5.193 supports MP Metrics 2.0 that introduces some breaking changes. It's not affected directly, but it seems a regression by some reason.