CPU limits don't work on RaspberryPi2

[om26er]

Required information

• Distribution: Ubuntu
• Distribution version: 16.04.1
• The output of "lxc info":

apiextensions:
- storage_zfs_remove_snapshots
- container_host_shutdown_timeout
- container_syscall_filtering
- auth_pki
- container_last_used_at
- etag
- patch
- usb_devices
- https_allowed_credentials
apistatus: stable
apiversion: "1.0"
auth: trusted
environment:
  addresses:
  - 10.193.98.1:8443
  - 192.168.1.99:8443
  architectures:
  - armv7l
  certificate: |
    -----BEGIN CERTIFICATE-----
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    MRwwGgYDVQQKExNsaW51eGNvbnRhaW5lcnMub3JnMRkwFwYDVQQDDBByb290QHJh
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    +hyfPsvrpg==
    -----END CERTIFICATE-----
  certificatefingerprint: d53952c9a4ced2c1f3f9fa2154890d935cefac9366bedc850cbd04a3e6a5e674
  driver: lxc
  driverversion: 2.0.4
  kernel: Linux
  kernelarchitecture: armv7l
  kernelversion: 4.4.0-1021-raspi2
  server: lxd
  serverpid: 3155
  serverversion: "2.1"
  storage: dir
  storageversion: ""
config:
  core.https_address: 0.0.0.0:8443
  core.trust_password: true
public: false

Issue description

CPU limits config does not work on a RPi2. My all 4 cores are always exposed to my containers

Steps to reproduce

lxc config set xenial limits.cpu 1
lxc start xenial
lxc shell xenial
$ cat /proc/cpuinfo | grep ^
   processor    : 0
   processor    : 1
   processor    : 2
   processor    : 3

Information to attach

• http://paste.ubuntu.com/23163881/ (dmesg)
• http://paste.ubuntu.com/23163892/ (lxc info xenial --show-log)
• http://paste.ubuntu.com/23163897/ (/var/log/lxd/lxd.log)

[rst0git]

Hi,
You have received the warning message in the log files:
"Couldn't find the CGroup CPUset controller, CPU pinning will be ignored"

#1554 --> Try to install apt-get install cgroups-lite

Also you can see in the source code here -> https://github.com/lxc/lxd/blob/master/lxd/daemon.go#L647
that this warning is resieved when the path "/sys/fs/cgroup/cpuset/" does not exist.

:) Hope this helps

[stgraber]

The fact that you only received two warnings instead of one for every controller, suggests that your kernel just doesn't have support for the pids and cpuset controllers which is a bit weird given that the other Ubuntu 4.4 kernels sure do.

So I'd recommend you check /proc/mounts to make sure that all the other controllers are mounted (by systemd) and if that's the case, then file a bug against the Ubuntu rpi2 kernel to have them enable those two cgroup controllers.