Hi,

I have OS ‘image’ that boots via PXE and mounts over NFS. (7.5.1804). I am wanting to explore allowing cgroup usage on this configuration.

The root image is exported read-only over NFS and am using statetab & rwtab to allow some persistent parts of the filesystem as well as read/write where needed.

I have tried setting /sys in the statetab and this causes the machine to fail, as I have tried /sys in the rwtab. The latter increases the boot time to a point which is not usable. Trying /sys/fs/cgroup in rwtab seems to improve boot time but also causes the machine not to complete booting.

I had some more success using cgconfig.conf, I was able to mount the memory cgroup to a local disk (each node has a local temp disk) and manipulate this using cgcreate but the cpu would not mount in the same fashion; the error was: Error: cannot mount cpu to /var/tmp/cgroup/cpu: Device or resource busy

So my question; in this particular environment, is how best to utilize cgroup if I want control over both cpu and mem? Is it possible with a read-only root image?

Thanks,