[lxc-devel] [Not A Patch] [POC] Proof of concept code for using devtmpfs for autodev and more...

[Michael H. Warfield]

On Fri, 2013-11-01 at 12:34 -0500, Serge Hallyn wrote: 
> Quoting Michael H. Warfield (mhw at WittsEnd.com):
> > On Thu, 2013-10-31 at 13:00 -0500, Serge Hallyn wrote: 
> > > Quoting Michael H. Warfield (mhw at WittsEnd.com):
> > > > I did incorporate your suggestion of using the hash of the rootfs path
> > > > as the subdirectory under the hosts /dev/ for the container.  I also
> > > 
> > > (Printed this out to look it over, just putting all my comments together
> > > here) :
> > > 
> > > 1. I think if /dev is not devtmpfs, we should just bail on this.
> > > 
> > > 2. You say in comments that you're using the cgroup name, but it seems
> > >    you're actually just using the container name?
> > 
> > Ok...  I'm going to experiment with this a bit but check me on this...
> > In the routine "lxc_setup()" the first parameter is "name".  Is that the
> > cgroup name or just the container name?  I take it, from your remark,
> > this is just the container name and the unique cgroup name may be
> > something different.

> Correct.

> But if you're using $(echo "$lxcpath.$lxcname" | sha1sum) why do you
> need the cgroup name?

The only place that's being used is in creating a symlink...

/dev/.lxc/$name -> /dev/.lxc/$pathhash

I use it for the same reason you wanted the extra bind mounts to
$lxcpath/$lxcname.dev.  In your case, you wanted to see the dev mappings
in the mount tables, in my case I was going for them in the symlinks
in /dev/.  It's so I can correlate a cgroup name and browsing the
cgroups with the same name in /dev/.lxc.

> > Is that something I should be pulling out of the
> > cgroup info structure?

> Yes.  I don't know offhand where though.

K  I'll look into that deeper.  Right now I'm going to play with this
whole idea of two containers with the same name and see how all that
works.

I'm also trying to figure out where those "rootfsproc" and "rootfssys"
subdirectories in /var/lib/lxc/$name/ are being creating.  I'm having a
hard time pinning them down in the source and I want to do something
similar for rootfsdev.

> -serge

Regards,
Mike
-- 
Michael H. Warfield (AI4NB) | (770) 985-6132 |  mhw at WittsEnd.com
   /\/\|=mhw=|\/\/          | (678) 463-0932 |  http://www.wittsend.com/mhw/
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