libvirt users - Jul 2016 - Re: How can I run command in containers on the host?

How can I run command in containers on the host? Just like the lxc command
lxc-attach.
I run :
virsh -c lxc:/// lxc-enter-namespace fedora2 --noseclabel /bin/ls

but get error:
libvirt:  error : Expected at least one file descriptor
error: internal error: Child process (14930) unexpected exit status 125

Here is my libvirt.xml

<domain type='lxc'>
   <name>fedora2</name>
   <memory>190000</memory>
   <vcpu>2</vcpu>
   <cputune>
     <shares>1000</shares>
   </cputune>
   <os>
  <features>
    <privnet/>
    <capabilities policy='allow'>
    </capabilities>
  </features>
   <type>exe</type>
   <init>/sbin/init</init>
   </os>
   <devices>
     <filesystem type="mount">
      <source dir="/home/lxc-fedora"></source>
      <target dir="/"></target>
   </filesystem>
     <console type='pty'/>
     <interface type='bridge'>
      <mac address='52:54:00:e8:96:88'/>
      <source bridge='virbr0'/>
      <target dev='vnet0'/>
      <guest dev='eth0'/>
    </interface>
   </devices>
</domain>


version of libvirt:
Compiled against library: libvirt 1.2.9
Using library: libvirt 1.2.9
Using API: QEMU 1.2.9
Running hypervisor: QEMU 2.1.2


Is there any mistake?

Thanks,
John

On Tue, Jul 26, 2016 at 04:58:40PM +0800, John Y. wrote:
> How can I run command in containers on the host? Just like the lxc command
> lxc-attach.
> I run :
> virsh -c lxc:/// lxc-enter-namespace fedora2 --noseclabel /bin/ls
> 
> but get error:
> libvirt:  error : Expected at least one file descriptor
> error: internal error: Child process (14930) unexpected exit status 125
[snip]
> Is there any mistake?
No, your example is correct. Can you try with

 LIBVIRT_DEBUG=1 virsh -c lxc:/// lxc-enter-namespace fedora2 --noseclabel
/bin/ls

so we can see if we get more useful debug info


Regards,
Daniel
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On Tue, Jul 26, 2016 at 05:19:22PM +0800, John Y. wrote:
> Hi Daniel,
> 
> I forgot to tell you that I using mips64 fedora. Has any effect on this
> case?
> 2016-07-26 09:05:59.634+0000: 16406: debug : virDomainLxcEnterNamespace:131
> : dom=0xaaad4067c0, (VM: name=fedora2,
> uuid=42b97e4d-54dc-41b4-b009-2321a1477a9a), nfdlist=0, fdlist=0xaaad4007c0,
> noldfdlist=(nil), oldfdlist=(nil), flags=0
> libvirt:  error : Expected at least one file descriptor
> error: internal error: Child process (16406) unexpected exit status 125
This is shows  nfdlist=0, whicih means that virDomainLxcOpenNamespace
didn't provide any file descriptors. This in turn seems to suggest
that /proc/$PID/ns didn't contain any files.

Is this perhaps a misconfiguration of the mips kernel.

Regards,
Daniel
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