Monthly Archives: July 2012

Nested Virtualization with Intel — take-2 with Fedora-17

My previous attempt with Fedora 16 to create a nested virtual guest on an Intel CPU was only 90% success,. I just gave a retry with Fedora 17, and the newest available virt packages from virt-preview repository.

I posted some notes, configurations of physical host, regular guest and nested guest, and the scripts I used on my fedora people page

Few observations:

  • Regular guest(L1) created just fine on the physical host(L0). No news here, this is expected.
  • Shutting down the regular guest causes ‘virsh’ to hang with a segfault. To avoid this, I have to restart libvirtd daemon, and then start the guest. I posted some more details to fedora virt list here and here
  • Now, when I try to create the ‘nested guest'(L2), I don’t see any progress on the serial console once it attempts to retrieve initrd and vmlinuz :

# ./create-nested-guest.bash 
Creating qcow2 disk image..
Formatting '/export/vmimgs/nested-guest-f17.qcow2', fmt=qcow2 size=10737418240 encryption=off cluster_size=65536 preallocation='metadata' 
11G -rw-r--r--. 1 root root 11G Jul 28 10:47 /export/vmimgs/nested-guest-f17.qcow2

Starting install...
Retrieving file .treeinfo...                                                                                                 | 1.8 kB     00:00 !!! 
Retrieving file vmlinuz...                                                                                                   | 8.9 MB     00:00 !!! 
Retrieving file initrd.img...                                                                                                |  47 MB     00:00 !!! 
Creating domain...                                                                                                           |    0 B     00:00     

I tried to view,using less or tail, system/libvirt logs, check status of libvirtd daemon, or try virsh list in the ‘regular guest’ to no avail. Those commands are just hung on the stdout.

A little bit more detail in a text file here.

Meanwhile, here’s the version detail. I used the same kernel, qemu-kvm, libvirt on both Physical host and Regular guest:

[root@moon ~]# uname -r ; rpm -q qemu-kvm libvirt 
[root@moon ~]# 

I’m still investigating, will update here, once I have more information.


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