Package org.apache.druid.java.util.metrics.cgroups

Class ProcCgroupV2Discoverer

java.lang.Object

org.apache.druid.java.util.metrics.cgroups.ProcCgroupDiscoverer

org.apache.druid.java.util.metrics.cgroups.ProcCgroupV2Discoverer

All Implemented Interfaces:

CgroupDiscoverer

public class ProcCgroupV2Discoverer
extends ProcCgroupDiscoverer

Field Summary

Fields inherited from class org.apache.druid.java.util.metrics.cgroups.ProcCgroupDiscoverer

procDir

Constructor Summary

Constructors

Constructor	Description
ProcCgroupV2Discoverer(Path procDir)	Create a proc discovery mechanism based on a `/proc` directory.

Method Summary

Modifier and Type	Method	Description
Path	discover(String cgroup)	Gets the path in the virtual FS for the given cgroup (cpu, mem, etc.).

Methods inherited from class org.apache.druid.java.util.metrics.cgroups.ProcCgroupDiscoverer

getMountEntry

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

ProcCgroupV2Discoverer

public ProcCgroupV2Discoverer(Path procDir)

Create a proc discovery mechanism based on a `/proc` directory.

Parameters:

procDir - The directory under proc. This is usually `/proc/self` or `/proc/#pid`

Method Details

discover

public Path discover(String cgroup)

Description copied from class: ProcCgroupDiscoverer

Gets the path in the virtual FS for the given cgroup (cpu, mem, etc.). The method first retrieves 2 paths: - The cgroup virtual FS mount point by calling /proc/mounts. This is usually like '/sys/fs/cgroup/cpu'. - The heirarchy path by calling /proc/[pid]/cgroup. In Docker this can look like '/docker/4b053f1267369a19dcdcb293e1b4d6b71fd0f26bf7711d589f19d48af92e6278' The method then tries to find the final virtual FS path by contenating the 2 paths first, and then falling back to the root virtual FS path. In this example, the method tries '/sys/fs/cgroup/cpu/docker/4b053f1267369a19dcdcb293e1b4d6b71fd0f26bf7711d589f19d48af92e6278' and then falls back to '/sys/fs/cgroup/cpu'. An exception is thrown if neither path exists.

Specified by:

discover in interface CgroupDiscoverer

Overrides:

discover in class ProcCgroupDiscoverer

Parameters:

cgroup - The cgroup.

Returns:

the virtual FS path.