Bug 1029070

Summary: libvirt-lxc: allow the use of a pre-populated /dev directory
Product: [Fedora] Fedora Reporter: Josh Poimboeuf <jpoimboe>
Component: libvirtAssignee: Daniel Berrangé <berrange>
Status: CLOSED NOTABUG QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: medium Docs Contact:
Priority: unspecified    
Version: rawhideCC: berrange, clalancette, itamar, jforbes, jyang, laine, libvirt-maint, veillard, virt-maint
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Hardware: All   
OS: Linux   
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Fixed In Version: Doc Type: Bug Fix
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Last Closed: 2014-01-23 15:54:28 UTC Type: Bug
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Description Josh Poimboeuf 2013-11-11 15:34:02 UTC 
The docker team has a concept called docker-in-docker where they want to spawn containers from within a container.  They already use the lxc tools for this purpose.

In my port of docker to use libvirt-lxc as its container backend, it would be very helpful to have this functionality.  Currently libvirt-lxc drops the CAP_MKNOD capability so it's not directly possible to start a container from inside an outer libvirt-lxc container, since the inner container creation logic creates a /dev/ tmpfs and then needs to mknod several device files.

As Daniel Berrange pointed out to me, allowing a container to mknod is very dangerous.  A much more acceptable solution would be to add a feature to libvirt-lxc to allow the use of an existing pre-populated /dev directory.
Comment 1 Josh Poimboeuf 2014-01-23 15:54:28 UTC 
I think we can cancel this bug now since the mknod issue will be solved by bug 1057200.