Installing ubuntu-core snap inside a LXD container fails

[Sujeevan Vijayakumaran]

Great, thanks for the clarification!

Am 07.06.2016 um 18:36 schrieb Stéphane Graber:
> On Wed, Jun 08, 2016 at 01:31:06AM +0900, Mark Shuttleworth wrote:
>> On 07/06/16 23:14, Claudio André wrote:
>>> 2016-06-07 9:37 GMT-03:00 Sujeevan (svij)
>>> Vijayakumaran <svij at ubuntu.com <mailto:svij at ubuntu.com>>: 
>>>
>>>     > That's because snapd tickles the kernel in a way that blows[...]
>>>
>>>
>>> That is interesting. Where I can find more about the 'tickles'? My
>>> motivation:
>>> - I'm seeing closed source software behaves badly, e.g, AMD software
>>> prints.
>>>
>>>   Internal Error:  as failed
>>>   Codegen phase failed compilation.
>>>
>>> If I know what the  'tickles' mean, I might be able to do something.  
>>> Thanks.
>>
>> I think it has to do with nesting kernel structures related to security
>> (LXD sets those up, then snapd wants to tweak them again), but a much
>> clearer answer would come from Stephane cc'd.
>>
>> Mark
> 
> Hi,
> 
> Containers cannot mount squashfs file systems, or setup loop mounts or
> setup apparmor profiles. All of which are required to get a snap
> running.
> 
> All of the above are blocked by the kernel as unsafe to use by an
> unprivileged user (which you are in a LXD container).
> 
> 
> My team is actively working on some kernel changes and some changes to
> snapd itself to allow this to work in the near future.
> 
> Stéphane
> 
>>
>>
>>>
>>> 2016-06-07 8:41 GMT-03:00 Sujeevan (svij) Vijayakumaran
>>> <svij at ubuntu.com <mailto:svij at ubuntu.com>>:
>>>
>>>     Hello!
>>>
>>>     I'm trying to install a snap inside a freshly created LXD container,
>>>     which isn't possible:
>>>
>>>     -----
>>>     ubuntu at snap-test:~$ sudo snap install
>>>     taskwarrior_2.5.1-snap0_amd64.snap
>>>     64.75 MB / 64.75 MB
>>>     [========================================================================]
>>>     100.00 % 5.38 MB/s
>>>
>>>     error: cannot perform the following tasks:
>>>     - Mount snap "ubuntu-core" ([start snap-ubuntu\x2dcore-122.mount]
>>>     failed
>>>     with exit status 1: Job for snap-ubuntu\x2dcore-122.mount failed. See
>>>     "systemctl status "snap-ubuntu\\x2dcore-122.mount"" and
>>>     "journalctl -xe"
>>>     for details.
>>>     )
>>>     ubuntu at snap-test:~$ systemctl status "snap-ubuntu\\x2dcore-122.mount"
>>>     ● snap-ubuntu\x2dcore-122.mount - Squashfs mount unit for ubuntu-core
>>>        Loaded: loaded (/etc/systemd/system/snap-ubuntu\x2dcore-122.mount;
>>>     enabled; vendor preset: enabled)
>>>        Active: failed (Result: exit-code) since Tue 2016-06-07
>>>     11:32:13 UTC;
>>>     16s ago
>>>         Where: /snap/ubuntu-core/122
>>>          What: /var/lib/snapd/snaps/ubuntu-core_122.snap
>>>       Process: 8584 ExecMount=/bin/mount
>>>     /var/lib/snapd/snaps/ubuntu-core_122.snap /snap/ubuntu-core/122
>>>     (code=exited, status=32)
>>>
>>>     Jun 07 11:32:13 snap-test systemd[1]: Mounting Squashfs mount unit for
>>>     ubuntu-core...
>>>     Jun 07 11:32:13 snap-test mount[8584]: mount: /snap/ubuntu-core/122:
>>>     mount failed: Unknown error -1
>>>     Jun 07 11:32:13 snap-test systemd[1]: snap-ubuntu\x2dcore-122.mount:
>>>     Mount process exited, code=exited status=32
>>>     Jun 07 11:32:13 snap-test systemd[1]: Failed to mount Squashfs mount
>>>     unit for ubuntu-core.
>>>     Jun 07 11:32:13 snap-test systemd[1]: snap-ubuntu\x2dcore-122.mount:
>>>     Unit entered failed state.
>>>     ------
>>>
>>>     It works fine if it's not inside a LXD container. Is this an issue
>>>     with
>>>     LXD or with snapd or am I missing something?
>>>
>>>     Also: Why is there an "ugly" \x2d (which seems to be a hypen-minus) in
>>>     the systemd-file rather than a "normal" minus?
>>>
>>>     Cheers,
>>>     Sujeevan
>>>
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>>>
>>>
>>>
>>>
>>
> 
> 
>