k8s incompability.

[jmormal]

Title: Crash on startup: NullPointerException in CgroupV2Subsystem (Cgroup v2 incompatibility)

Description

When deploying Mintaka (both 0.6.18 and 0.7.0) on a Kubernetes cluster with Cgroup v2 enabled, the application crashes immediately on startup due to a NullPointerException in the Java Runtime's Cgroup v2 detection logic.

This appears to be caused by the Micronaut metrics system trying to read system limits using a JDK version that has incomplete or buggy support for the host's Cgroup v2 layout.

Steps to Reproduce

1. Deploy quay.io/fiware/mintaka:0.7.0 on a Kubernetes cluster (e.g., Minikube, K3s, or standard K8s v1.25+) running on a Linux host with Cgroup v2 enabled.
2. Observe the pod logs.

Observed Logs

mintaka     at io.micronaut.runtime.Micronaut.run(Micronaut.java:323)
mintaka     at org.fiware.mintaka.Application.main(Application.java:29)
mintaka Caused by: java.lang.NullPointerException: Cannot invoke "jdk.internal.platform.CgroupInfo.getMountPoint()" because "anyController" is null
mintaka     at java.base/jdk.internal.platform.cgroupv2.CgroupV2Subsystem.getInstance(CgroupV2Subsystem.java:80)
mintaka     at java.base/jdk.internal.platform.CgroupSubsystemFactory.create(CgroupSubsystemFactory.java:114)
mintaka     at java.base/jdk.internal.platform.CgroupMetrics.getInstance(CgroupMetrics.java:177)
mintaka     at java.base/jdk.internal.platform.SystemMetrics.instance(SystemMetrics.java:29)
...
mintaka     at io.micrometer.core.instrument.binder.system.ProcessorMetrics.<init>(ProcessorMetrics.java:81)

Environment
Mintaka Version: 0.7.0 (and 0.6.18)

Orchestrator: Kubernetes (Cgroup v2 enabled)

Java Runtime: (As provided in the Docker image)

Workaround
Forcing the Micronaut metrics to be disabled prevents the crash:

YAML

env:

• name: MICRONAUT_METRICS_ENABLED
  value: "false"
  Suggested Fix
  This seems to be related to an older JDK bug (e.g., JDK-8287073).

Please verify if the base Docker image can be updated to a more recent patch version of OpenJDK (JDK 17.0.5+ or JDK 21) that fully supports Cgroup v2.

Alternatively, handle the NullPointerException in the metrics initialization so the app does not crash if metrics cannot be gathered.