p.haul: LinuX Containers hauler module (v2)

Known issues:
* It works only in one direction, because the lxc control
  process isn't executed after migration.

v2: add support of veth devices

[root@40 p.haul]# ./p.haul lxc centos-lxc-4 192.168.122.36
Loading config file from /var/lib/lxc/centos-lxc-4/config
Connecting to target host
Initilized shared FS hauler
Connecting to CRIU service
Preliminary FS migration
Starting iterations
* Iteration 0
        Making directory /var/local/p.haul-fs/rDf7q4/img/1
        Issuing pre-dump command to service
        Pre-dump succeeded
Dumped 2508 pages, 0 skipped
Checking iteration progress:
        > Proceed to next iteration
* Iteration 1
        Making directory /var/local/p.haul-fs/rDf7q4/img/2
        Issuing pre-dump command to service
        Pre-dump succeeded
Dumped 39 pages, 2469 skipped
Checking iteration progress:
        > Small dump
Final dump and restore
        Making directory /var/local/p.haul-fs/rDf7q4/img/3
        Issuing dump command to service
                Notify (network-lock)
Dump complete
Final FS and images sync
Sending images to target
        Pack
        Add htype images
        Save CG for 6212 into /var/local/p.haul-fs/rDf7q4/img/3/lxccg.img
        Copy
        Unpack
Asking target host to restore
Final dump -- 25 pages, 2483 skipped
Removing images
Migration succeeded
           total time is ~3.08 sec
          frozen time is ~2.71 sec ( ['0.08', '0.11', '2.52'] )
         restore time is ~1.83 sec
        img sync time is ~0.31 sec

lxc

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>