[lxc-users] lxc stateful snapshot fails with "Pre dump script failed with 32512"

[Alex Kedrowitsch]

Hi All,

I'm new to the Linux container scene and am having issues with making
stateful container snapshots. My ultimate goal is to get "lxc move" to
work, but that fails with the same error as when I try "lxc snapshot <>
--stateful", so I'm starting with the lowest common denominator.

Environment:
VM running Ubuntu 16.04, Kernel 4.4.0-31-generic
LXD version 2.0.3
CRIU version 2.0 (no special commits)

I am following the steps outlined here: (
http://insights.ubuntu.com/2016/04/25/lxd-2-0-live-migration-912/) as well
as trying to match the requirements here: (
https://insights.ubuntu.com/2015/05/06/live-migration-in-lxd/) (this second
article is invaluable, but would be great if it was updated for the latest
changes to LXD, like not including the step to remove lxcfs, which broke my
installation of LXD when I did.)

I was previously able to make stateful snapshots without error, but was
unable to restore them; however, today I am unable to even make the
snapshots.  Stateless snapshots can be made without error.

Appears to be similar to this issue (https://github.com/lxc/lxd/issues/2110),
where stgraber believes it's a bug with CRIU serializing sockets, but I was
unable to find the bug report on Launchpad.

Here are my logs.  Thanks for the help!

Terminal Commands/output:
alex at osboxesDesktop:~$ lxc snapshot stringhalty-judie snap2 --stateful
error: snapshot dump failed
(00.041465) Error (action-scripts.c:60): One of more action scripts failed
(00.041478) Error (cr-dump.c:1621): Pre dump script failed with 32512!

Container info:
alex at osboxesDesktop:~$ lxc info stringhalty-judie
Name: stringhalty-judie
Architecture: x86_64
Created: 2016/08/03 20:07 UTC
Status: Running
Type: persistent
Profiles: default
Pid: 9665
Ips:
  eth0:    inet    10.29.26.131    vethBI73UQ
  eth0:    inet6    fe80::216:3eff:fe38:4351    vethBI73UQ
  lo:    inet    127.0.0.1
  lo:    inet6    ::1
Resources:
  Processes: 26
  Memory usage:
    Memory (current): 41.85MB
    Memory (peak): 179.00MB
  Network usage:
    lo:
      Bytes received: 264 bytes
      Bytes sent: 264 bytes
      Packets received: 4
      Packets sent: 4
    eth0:
      Bytes received: 6.60kB
      Bytes sent: 2.17kB
      Packets received: 43
      Packets sent: 17
Snapshots:
  snap1 (taken at 2016/08/03 20:49 UTC) (stateless)

snapshot_dump_###.log:
(00.000023) Probing sock diag modules
(00.000053) Done probing
(00.028278) ========================================
(00.028291) Dumping processes (pid: 9665)
(00.028292) ========================================
(00.028293) Running pre-dump scripts
(00.028306)     [@ÑÙ È]
(00.041465) Error (action-scripts.c:60): One of more action scripts failed
(00.041478) Error (cr-dump.c:1621): Pre dump script failed with 32512!


Excerpt from lxc.log:
            lxc 20160803171813.590 DEBUG    lxc_commands -
commands.c:lxc_cmd_get_state:579 - 'stringhalty-judie' is in 'RUNNING' state
            lxc 20160803171819.956 INFO     lxc_confile -
confile.c:config_idmap:1520 - read uid map: type u nsid 0 hostid 231072
range 65536
            lxc 20160803171819.956 INFO     lxc_confile -
confile.c:config_idmap:1520 - read uid map: type g nsid 0 hostid 231072
range 65536
            lxc 20160803171819.957 DEBUG    lxc_commands -
commands.c:lxc_cmd_handler:893 - peer has disconnected
            lxc 20160803171819.957 DEBUG    lxc_commands -
commands.c:lxc_cmd_handler:893 - peer has disconnected
            lxc 20160803171819.957 DEBUG    lxc_commands -
commands.c:lxc_cmd_get_state:579 - 'stringhalty-judie' is in 'RUNNING' state
            lxc 20160803171819.963 DEBUG    lxc_commands -
commands.c:lxc_cmd_handler:893 - peer has disconnected
            lxc 20160803171819.975 DEBUG    lxc_commands -
commands.c:lxc_cmd_handler:893 - peer has disconnected
            lxc 20160803171819.975 INFO     lxc_criu - criu.c:exec_criu:422
- execing: /usr/sbin/criu dump --tcp-established --file-locks --link-remap
--manage-cgroups=full --ext-mount-map auto --enable-external-sharing
--enable-external-masters --enable-fs hugetlbfs --enable-fs tracefs -D
/var/lib/lxd/containers/stringhalty-judie/state -o
/var/lib/lxd/containers/stringhalty-judie/state/dump.log -vvvvvv
--action-script \D0\D1\DE \C8 -t 9665 --freeze-cgroup
/sys/fs/cgroup/freezer///lxc/stringhalty-judie --ext-mount-map
/dev/console:console --external tty[8812:e] --force-irmap --ghost-limit
859535847452 --leave-running
            lxc 20160803171819.975 DEBUG    lxc_commands -
commands.c:lxc_cmd_handler:893 - peer has disconnected
            lxc 20160803171820.142 ERROR    lxc_criu - criu.c:do_dump:930 -
dump signaled with 11
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