[lxc-users] Device node in LXC is not accessible when connected via SSH

[Tim Jaacks]

> -----Ursprüngliche Nachricht-----
> Von: Serge E. Hallyn <serge at hallyn.com> 
> Gesendet: Montag, 3. Februar 2020 12:36
> An: Tim Jaacks <tim.jaacks at garz-fricke.com>
> Cc: Serge E. Hallyn <serge at hallyn.com>; LXC users mailing-list <lxc-users at lists.linuxcontainers.org>
> Betreff: Re: [lxc-users] Device node in LXC is not accessible when connected via SSH
> 
> On Mon, Feb 03, 2020 at 10:02:27AM +0000, Tim Jaacks wrote:
> > OK, this shows me "/lxc/mylxc/init.scope", which sounds reasonable. So do you have any idea, which using "sudo lxc-attach" results in the wrong cgroup "/user.slice"?
> 
> You can check for an 'lxc.cgroup.keep' entry in your container configuration.  

Nope, I don't have that option set.

> The lxc-attach manpages has a note from Feb 2016 about how "previous versions"
> "suffered a bug whereby a user could attach to a containers namespace without being placed in a writeable cgroup for some critical subsystems."  If you're on an older version, it could be that.

I am running LXC version 3.0.3, which is the default on Debian Buster:
https://packages.debian.org/buster/lxc

Is that an "older version"?

I have tried the same commands on an Ubuntu 18.04 machine, also running LXC 3.0.3:

    sudo lxc-create -q -t debian -n mylxc -- -r stretch
    sudo lxc-start -n mylxc
    sudo lxc-attach -n mylxc

It puts the lxc-attach process into the /user.slice device cgroup as well. So I can reproduce this behavior on two different machines with different Linux distributions, both running LXC 3.0.3. Can anybody try to reproduce it with a newer LXC version?

> Otherwise, I'd say it's a bug.
> 
> -serge
>