[libvirt] [PATCH v2 00/21] Run qemu under its own namespace

[Daniel P. Berrange]

On Mon, Dec 12, 2016 at 11:48:50AM +0000, Daniel P. Berrange wrote:
> On Wed, Dec 07, 2016 at 09:36:07AM +0100, Michal Privoznik wrote:
> > v1 posted here:
> >   https://www.redhat.com/archives/libvir-list/2016-November/msg01208.html
> > 
> > diff to v1:
> > - I've dropped the patches for hugepages which are posted separately [1]
> > - I've reworked some parts according to Dan's suggestions
> > - Filled missing impl for virSCSIVHostDevice which was merged meanwhile
> > 
> > Please note that patches 1-5, 7 were ACKed already.
> > 
> > You can also find the patches on my github:
> > 
> >   https://github.com/zippy2/libvirt/tree/qemu_container_v3
> 
> I pulled this branch and aside from the compile error i mention I can't
> start guests
> 
> error: internal error: process exited while connecting to monitor: 2016-12-12T11:47:53.740784Z qemu-system-x86_64: -chardev pty,id=charserial0: Failed to create PTY: No such file or directory
> 
> 
> Without having investigated, I wonder if it is trying to access the
> /dev/ptmx file and failing ?  The /dev/ptmx file needs to be a symlink
> to /dev/pts/ptmx and I'm not seeing code which creates that yet.

Ok, in fact it is exactly the opposite problem :-)

You have done a bind mount of /dev/pts/ptmx -> /dev/ptmx, which ought to
be fine, except on Fedora 25 for some reason the /dev/pts/ptmx file is
created c-------- so nothing has privileges to access it. Instead Fedora
uses a real /dev/ptmx device node.

I guess this way Fedora works is ok, because you only need the /dev/ptmx
symlink / bind mount, if we created a *new* devpts mount instance - but
we're just reusing the host instance.

IOW, just modify qemuDomainBuildNamespace to remove the bind mount of
/dev/ptmx entirely, and QEMU starts.


After that, my next problem is lack of /dev/shm break SPICE graphics.

We should treat /dev/shm the same way we treat /dev/pts - just preserve
the existing host /dev/shm mount point (if it exists)

Regards,
Daniel
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