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

Thu Aug 4 14:47:17 UTC 2016

Hi Alex,

On Wed, Aug 03, 2016 at 05:44:56PM -0400, Alex Kedrowitsch wrote:
> 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.)

Good point, I should probably write an updated post :). Anyway,
stgraber's post here:

https://www.stgraber.org/2016/04/25/lxd-2-0-live-migration-912/

is pretty recent (i.e. migration should be pretty "no frills" right
now).

> 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!

Are you using a custom built liblxc? Looks like you might be missing
ebb088e115fd81f86602af8a386ee41470c71a73.

Tycho

> 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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