need phablet support for mods to /etc/lxc/lxc-usernet (vivid+stable ppa overaly)

[kevin gunn]

we have a need for phablet to use a network inside a container, currently the /etc/lxc/lxc-usernet file is readonly
would need to be modified to contain something like
phablet veth lxcbr0 10

[Serge Hallyn (serge-hallyn)]

This seems like something the phablet packages should do in a postinst, right?

Or are you asking for the Ubuntu lxc package to add this to the default lxc-usernet file which is installed on all systems?

(Asking since this is marked as affecting lxc)

[Christopher Townsend (townsend)]

Hi Serge,

Well, the problem is that /etc/lxc/lxc-usernet is read-only, so it can't be modified by a user action. I'm not really sure how modifications of system files is supposed to take place in the New World.

I think for a short-term solution, we can take the Vivid lxc source package and modify it to add a static 'phablet' entry in /lxc-usernet and upload it to the overlay PPA.

Long term, I'm not so sure about...

[Serge Hallyn (serge-hallyn)]

Quoting Christopher Townsend (<email address hidden>):
> Hi Serge,
>
> Well, the problem is that /etc/lxc/lxc-usernet is read-only, so it can't
> be modified by a user action. I'm not really sure how modifications of

Oh! I see, this is in snappy?

> system files is supposed to take place in the New World.

Yeah, me neither. Thanks for the clarification.

> I think for a short-term solution, we can take the Vivid lxc source
> package and modify it to add a static 'phablet' entry in /lxc-usernet
> and upload it to the overlay PPA.
>
> Long term, I'm not so sure about...

I'm sure there must be a "proper" way to do this sort of thing, let's
ask on #ubuntu-devel :)

thanks!

[Pat McGowan (pat-mcgowan)]

This is for pocket desktop support

[kevin gunn (kgunn72)]

@serge - ok to put your name as you might be able to help us here ? ping me on irc if you need

[kevin gunn (kgunn72)]

chris pointed out that this isn't really needed for pd as we're using a custom chroot not lxc.
but leaving this open as we'll want this eventually.

[Serge Hallyn (serge-hallyn)]

@kgunn72,

depends on what you need. I'm happy to answer any questions, but I don't think i know enough to drive this.

If all you really need is to have a phablet line in the lxc-usernet file as shipped in the package, then probably best for @stgraber to add it.

[Stéphane Graber (stgraber)]

Having a special username hardcoded in there seems wrong to me.
Eventually we will want to do proper multi-user on those devices or allow users to rename the user at which point everything will break again.

What we may consider though is having LXC setup a new lxc-net group with a matching group entry in /etc/lxc/lxc-usernet so that any member of that group gets 10 veth in lxcbr0.

For that we'll need LXC 2.0 as I don't believe the lxc-usernet group support existed back in 1.1.

[Christopher Townsend (townsend)]

Hey Stéphane,

I agree that hardcoding the phablet user is not the best way to go about this. This is really only needed for The Future in which devices use a kernel that supports unprivileged containers. I think at this juncture, going about the way where members of a lxc-net group automatically get 10 veth devices is best.