Messages in this thread | | | From | Aditya Kali <> | Date | Tue, 6 Jan 2015 15:20:38 -0800 | Subject | Re: [PATCHv3 8/8] cgroup: Add documentation for cgroup namespaces |
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I understand your point. But it will add some complexity to the code.
Before trying to make it work for non-unified hierarchy cases, I would like to get a clearer idea. What do you expect to be mounted when you run: container:/ # mount -t cgroup none /sys/fs/cgroup/ from inside the container?
Note that cgroup-namespace wont be able to change the way cgroups are mounted .. i.e., if say cpu and cpuacct subsystems are mounted together at a single mount-point, then we cannot mount them any other way (inside a container or outside). This restriction exists today and cgroup-namespaces won't change that.
So, If on the host we have: root@adityakali-vm2:/sys/fs/cgroup# cat /proc/mounts | grep cgroup tmpfs /sys/fs/cgroup tmpfs rw,relatime 0 0 cgroup /sys/fs/cgroup/cpu cgroup rw,relatime,cpuset,cpu,cpuacct 0 0 cgroup /sys/fs/cgroup/mem cgroup rw,relatime,memory,hugetlb 0 0 cgroup /sys/fs/cgroup/rest cgroup rw,relatime,devices,freezer,net_cls,blkio,perf_event,net_prio 0 0
And inside the container we want each subsystem to be on its own mount-point, then it will fail. Do you think even then its useful to support virtualizing paths for non-unified hierarchies?
Thanks,
On Mon, Jan 5, 2015 at 4:17 PM, Richard Weinberger <richard@nod.at> wrote: > Am 06.01.2015 um 01:10 schrieb Aditya Kali: >> Since the old/default behavior is on its way out, I didn't invest time >> in fixing that. Also, some of the properties that make >> cgroup-namespace simpler are only provided by unified hierarchy (for >> example: a single root-cgroup per container). > > Does the new sane cgroupfs behavior even have a single real world user? > I always thought it isn't stable yet. > > Linux distros currently use systemd v210. They don't dare to use a newer one. > Even *if* systemd would support the sane sane cgroupfs behavior in the most recent > version it will take 1-2 years until it would hit a recent distro. > > So please support also the old and nasty behavior such that one day we can run current > systemd distros in Linux containers. > > Thanks, > //richard
-- Aditya
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