[Lxc-users] cgroup question

[Kevin Wilson]

Serge,
Thanks a lot, this explains everything.

With "dpkg -l | grep cgroup" I found cgroup-lite,
which includes /bin/cgroups-mount  and /bin/cgroups-umount
scripts.
After removing this package and rebooting, cat /proc/mounts | grep cgroup
show nothing.

I don't know for what is this package intended, and whether it is
fully safe to remove it, but I believe I am able to look for it.

 http://packages.ubuntu.com/search?keywords=cgroup-lite

Thanks,
Kevin


On Fri, Apr 12, 2013 at 7:13 PM, Serge Hallyn <serge.hallyn at ubuntu.com> wrote:
> Quoting Kevin Wilson (wkevils at gmail.com):
>> Hello,
>> Thanks a lot for your answer.
>>
>> I reproduced the problem:
>> this is what I run: (after boot, in  Ubuntu 12.10)
>>
>> mount -t tmpfs    cgroup_root    /cgroup
>>
>> mkdir /cgroup/test1
>> mount -t cgroup -o cpuset,devices mytest    /cgroup/test1
>>
>> And I get:
>> mount: mytest already mounted or /cgroup/test1 busy
>>
>> shouldn't it work ?
>>
>> I tried it on Ubuntu.
>> I was surprised to see that some cgroup contolkers are  mounted
>> under /sys/fs/cgroup (though it seems to me that this should not cause
>> a problem).
>
> It wouldn't cause a problem if you were mounting them separately,
> but you are asking for controllers to be bound together, which have
> already been separately mounted.  That is not possible.
>
> So for instance
>
> mkdir /tmp/1 /tmp/2 /tmp/3
> mount -t cgroup -o freezer /tmp/1
> mount -t cgroup -o freezer /tmp/2
> mount -t cgroup -o freezer /tmp/3
>
> is ok, but
>
> mkdir /tmp/1 /tmp/2 /tmp/3
> mount -t cgroup -o freezer /tmp/1
> mount -t cgroup -o cpuset /tmp/2
> mount -t cgroup -o cpuset,freezer /tmp/3
>
> is not
>
>> systemd is not running on Ubuntu, I don't have any idea
>> who
>> mounted in boot time the /sys/fs/cgroup contollers and for which purpose
>>
>> mount | grep cgroup
>> gives:
>> cgroup on /sys/fs/cgroup type tmpfs (rw,relatime,mode=755)
>> cgroup on /sys/fs/cgroup/cpuset type cgroup (rw,relatime,cpuset)
>> cgroup on /sys/fs/cgroup/cpu type cgroup (rw,relatime,cpu)
>> cgroup on /sys/fs/cgroup/cpuacct type cgroup (rw,relatime,cpuacct)
>> cgroup on /sys/fs/cgroup/memory type cgroup (rw,relatime,memory)
>> cgroup_root on /cgroup type tmpfs (rw)
>
> look for a cgroup related package, or lines in your fstab:
>
> dpkg -l | grep cgroup
> grep cgroup /etc/fstab
>
> -serge