[Bug 1342960] Re: Error setting cgroup devices.deny limit with nested lxc container

[Serge Hallyn]

Thanks for verifying.  What is happening is actually vaguely explained
in the mountcgroup hook itself, and is an unfortunate side effect of a
somewhat recent kernel change:

cd /sys/fs/cgroup/devices
sudo mkdir a
echo  a | sudo tee -a a/devices.deny   # succeeds
sudo mkdir -p b/c
echo a | sudo tee -a b/devices.deny    # fails

If a devices cgroup has any child cgroups, then you can no longer make
certain changes to it.

Marking this confirmed and changing the title to reflect that the
comments in /usr/share/lxc/config/ubuntu.common.conf need to be changed.

** Changed in: lxc
       Status: Incomplete => Triaged

** Also affects: lxc (Ubuntu)
   Importance: Undecided
       Status: New

** Also affects: lxc (Ubuntu Trusty)
   Importance: Undecided
       Status: New

** Changed in: lxc (Ubuntu)
       Status: New => Triaged

** Changed in: lxc (Ubuntu Trusty)
       Status: New => Triaged

** Changed in: lxc (Ubuntu Trusty)
   Importance: Undecided => High

** Changed in: lxc (Ubuntu)
   Importance: Undecided => High

** Summary changed:

- Error setting cgroup devices.deny limit with nested lxc container
+ comments in common.conf must be updated

** Changed in: lxc
     Assignee: (unassigned) => Serge Hallyn (serge-hallyn)

** Changed in: lxc
       Status: Triaged => In Progress

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https://bugs.launchpad.net/bugs/1342960

Title:
  comments in common.conf must be updated

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