[libvirt-users] cgroups inside LXC containers losts memory limits after some time

[mxs kolo]

Hi all

I have CentOS Linux release 7.0.1406, libvirt 1.2.7 installed.
Just after create and start inside LXC container present cgroups.
Example for memory:

[root at ce7-t1 /]# ls -la /sys/fs/cgroup/memory/
total 0
drwxr-xr-x  2 root root   0 Sep 15 17:14 .
drwxr-xr-x 12 root root 280 Sep 15 17:14 ..
-rw-r--r--  1 root root   0 Sep 15 17:14 cgroup.clone_children
--w--w--w-  1 root root   0 Sep 15 17:14 cgroup.event_control
-rw-r--r--  1 root root   0 Sep 15 17:15 cgroup.procs
-rw-r--r--  1 root root   0 Sep 15 17:14 memory.failcnt
--w-------  1 root root   0 Sep 15 17:14 memory.force_empty
-rw-r--r--  1 root root   0 Sep 15 17:14 memory.kmem.failcnt
-rw-r--r--  1 root root   0 Sep 15 17:14 memory.kmem.limit_in_bytes
-rw-r--r--  1 root root   0 Sep 15 17:14 memory.kmem.max_usage_in_bytes
-r--r--r--  1 root root   0 Sep 15 17:14 memory.kmem.slabinfo
-rw-r--r--  1 root root   0 Sep 15 17:14 memory.kmem.tcp.failcnt
-rw-r--r--  1 root root   0 Sep 15 17:14 memory.kmem.tcp.limit_in_bytes
-rw-r--r--  1 root root   0 Sep 15 17:14 memory.kmem.tcp.max_usage_in_bytes
-r--r--r--  1 root root   0 Sep 15 17:14 memory.kmem.tcp.usage_in_bytes
-r--r--r--  1 root root   0 Sep 15 17:14 memory.kmem.usage_in_bytes
-rw-r--r--  1 root root   0 Sep 15 17:14 memory.limit_in_bytes
-rw-r--r--  1 root root   0 Sep 15 17:14 memory.max_usage_in_bytes
-rw-r--r--  1 root root   0 Sep 15 17:14 memory.memsw.failcnt
-rw-r--r--  1 root root   0 Sep 15 17:14 memory.memsw.limit_in_bytes
-rw-r--r--  1 root root   0 Sep 15 17:14 memory.memsw.max_usage_in_bytes
-r--r--r--  1 root root   0 Sep 15 17:14 memory.memsw.usage_in_bytes
-rw-r--r--  1 root root   0 Sep 15 17:14 memory.move_charge_at_immigrate
-r--r--r--  1 root root   0 Sep 15 17:14 memory.numa_stat
-rw-r--r--  1 root root   0 Sep 15 17:14 memory.oom_control
----------  1 root root   0 Sep 15 17:14 memory.pressure_level
-rw-r--r--  1 root root   0 Sep 15 17:14 memory.soft_limit_in_bytes
-r--r--r--  1 root root   0 Sep 15 17:14 memory.stat
-rw-r--r--  1 root root   0 Sep 15 17:14 memory.swappiness
-r--r--r--  1 root root   0 Sep 15 17:14 memory.usage_in_bytes
-rw-r--r--  1 root root   0 Sep 15 17:14 memory.use_hierarchy
-rw-r--r--  1 root root   0 Sep 15 17:14 notify_on_release
-rw-r--r--  1 root root   0 Sep 15 17:14 tasks

Command "free" inside LXC showed almost normal values:
[root at ce7-t1 /]# free
             total       used       free     shared    buffers     cached
Mem:       1048576      32972    1015604    4473848          0   -4445364
-/+ buffers/cache:    4478336   -3429760
Swap:      1048576          0    1048576

(some problem with negative values)

After unpredictable time passed (1-5 day ?), cgroups inside LXC
magicaly removed. "free" in such containers show 2^53-1 as maximum
values:
[root at puppet01 /]# free
             total       used       free     shared    buffers     cached
Mem:    9007199254740991     591180 9007199254149811          0
  0     267924
-/+ buffers/cache:     323256 9007199254417735
Swap:            0          0          0

And no more any cgroups presented at least in memory category:
[root at puppet01 /]# ls -la   /sys/fs/cgroup/memory/
total 0


b.r.
 Maxim Kozin