[libvirt-users] libvirt_lxc and sysfs

[свящ. Георгий Гольцов]

On Mon, Jun 10, 2013 at 09:07:08AM +0800, Gao feng wrote:
> On 06/09/2013 08:14 PM, pr.G wrote:
> > Hello.
> > 
> > Is it possible to start container via libvirt_lxc without mounting /sys
> > inside container?
> > 
> > When I start container via lxc-start and do not add mount point to config, 
> > then /sys inside container is empty.
> > 
> > When I do it via virsh -c lxc:// container.xml, then 
> > /sys contains sysfs of the host and /sys on host becomes remounting read-only.
> 
> how can it be true? Can you post your /proc/mounts on host and container?
> 
> > 
> > Am I doing something wrong or is this feature of libvirt_lxc? 
> > 
> 
> Absolutely it's not a feature.
> 
> Thanks!
> 
Thanks for the quick reply.
I was surprised too. I didn't post /proc/mounts to container.
libvirt_lxc did it for me.
I read http://libvirt.org/drvlxc.html about Filesystem mounts:
"
In the absence of any explicit configuration, the container will
inherit the host OS filesystem mounts. A number of mount points will be
made read only, or re-mounted with new instances to provide container
specific data. The following special mounts are setup by libvirt

    * /dev a new "tmpfs" pre-populated with authorized device nodes
    * /dev/pts a new private "devpts" instance for console devices
    * /sys the host "sysfs" instance remounted read-only
    * /proc a new instance of the "proc" filesystem
    * /proc/sys the host "/proc/sys" bind-mounted read-only
    * /sys/fs/selinux the host "selinux" instance remounted read-only
    * /sys/fs/cgroup/NNNN the host cgroups controllers bind-mounted to
    * only expose the sub-tree associated with the container
    * /proc/meminfo a FUSE backed file reflecting memory limits of the
    * container
"
Can I disable this behavior? 
How do I specify an explicit configuration?
Thanks.

my container.xml: (The entire xml file is shown in the my original post)
> ...
>   <devices>
>     <emulator>/usr/lib/libvirt/libvirt_lxc</emulator>
>     <filesystem type='mount'>
>       <source dir='/var/lxc/ns1/rootfs'/>
>       <target dir='/'/>
>     </filesystem>
>  ...
>    </device>
>  ...
 

> > Thanks.
> > 
> > root at host:~# uname -a
> > Linux host 3.2.0-4-amd64 #1 SMP Debian 3.2.41-2+deb7u2 x86_64 GNU/Linux
> > 
> > root at host:~# cat /etc/os-release 
> > PRETTY_NAME="Debian GNU/Linux 7.0 (wheezy)"
> > ...
> > 
> > root at host:~# dpkg -l | grep libvirt
> > ii  libvirt-bin   0.9.12-11 amd64   programs for the libvirt library
> > ii  libvirt0      0.9.12-11 amd64   library for interfacing with different virtualization systems
> > 
> > 
> > container.xml:
> > <domain type='lxc'>
> >   <name>ns1</name>
> >   <memory>524288</memory>
> >   <os>
> >     <type>exe</type>
> >     <init>/sbin/init</init>
> >   </os>
> >   <vcpu>1</vcpu>
> >   <clock offset='utc'/>
> >   <on_poweroff>destroy</on_poweroff>
> >   <on_reboot>restart</on_reboot>
> >   <on_crash>destroy</on_crash>
> >   <devices>
> >     <emulator>/usr/lib/libvirt/libvirt_lxc</emulator>
> >     <filesystem type='mount'>
> >       <source dir='/var/lxc/ns1/rootfs'/>
> >       <target dir='/'/>
> >     </filesystem>
> >     <interface type='bridge'>
> >       <source bridge='br0'/>
> >       <mac address='52:54:00:de:74:06'/>
> >     </interface>
> >     <console type='pty' />
> >   </devices>
> > </domain>
> > 
> > 
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> > 
>