CODEWITHSUNDEEP
linuxlinux-kernelresourcesdockercgroups
Viacheslav Kovalev
Viacheslav Kovalev

Reputation: 1745

Read cgroups data without mounting it

I have some cgroups-managed services (actually running in docker). To fairly schedule some resource-demanding tasks, containerized services need to know it exact (as far as possible) resource usage. I've decided to read this metrics from cgroups.

But there is a problem. I known two ways to access cgroup data from docker container.

  1. Mount cgroups directly from the inside of container. To accomplish that, I need to give CAP_SYS_ADMIN capability to container. I think this is too hard-boiled way to only read resource usage metrics.

  2. Use docker volume, pointing to host cgroups mountpoint. This solution more or less appropriate, but I'am lookin' more elegant way.

I am not an "kernel-guy" and not familiar with kernel sources and documentation, so I am able to ask noob's question.

Is there any kernel interface which allows me to read cgroups metrics without mounting cgroups filesystem?

Upvotes: 1

Views: 563

Answers (1)

askb
askb

Reputation: 6768

The only interface you get in the user space is by mounting cgroups or from the /proc/<pid>/cgourps, (but only limited to the cgroups a process belongs to). If you are looking for a syscall() for reading cgroups data, its not available IMU. Docker requires cgroups services (cgconfig, cgred, etc)to be running, therefore its would require you to mount the cgroups.

Upvotes: 2

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