[SOLVED] virt-install: permission denied accessing qcow2 formatted volume

ordinary · 10-01-2012, 05:03 PM

I am trying to install a virtual machine using virt-install on a Debian Squeeze host, and it fails complaining that permission is denied accessing the virtual disk. It doesn't have any problem creating the virtual disk, but it cannot access it to complete the installation. Help or advice would be appreciated.

In the first place, /var/lib/libvirt/images is empty

Code:

phil@frederic:/var/lib/libvirt/images$ pwd
/var/lib/libvirt/images
phil@frederic:/var/lib/libvirt/images$ ls -l
total 16
drwx------ 2 root root 16384 Sep 29 22:17 lost+found
phil@frederic:/var/lib/libvirt/images$

I tried virt-install with the necessary options to create a virtual disk image:

Code:

phil@frederic:~$ sudo virt-install --name vm-fififi --ram 512  --disk /var/lib/libvirt/images/vm-fififi.img,size=12,format=qcow2 --cdrom /home/phil/Downloads/ubuntu-12.04.1-server-amd64.iso --vnc --noautoconsole --os-type linux  --network=bridge:br1,mac=52:54:00:a3:88:df


Starting install...
Allocating 'vm-fififi.img'                                                                                                                                                                                        |  12 GB     00:00     
ERROR    internal error Process exited while reading console log output: char device redirected to /dev/pts/1
qemu: could not open disk image /var/lib/libvirt/images/vm-fififi.img: Permission denied

Domain installation does not appear to have been
 successful.  If it was, you can restart your domain
 by running 'virsh start vm-fififi'; otherwise, please
 restart your installation.
ERROR    internal error Process exited while reading console log output: char device redirected to /dev/pts/1
qemu: could not open disk image /var/lib/libvirt/images/vm-fififi.img: Permission denied
Traceback (most recent call last):
  File "/usr/bin/virt-install", line 1033, in <module>
    main()
  File "/usr/bin/virt-install", line 915, in main
    start_time, guest.start_install)
  File "/usr/bin/virt-install", line 957, in do_install
    dom = install_func(conscb, progresscb, wait=(not wait))
  File "/usr/lib/pymodules/python2.6/virtinst/Guest.py", line 973, in start_install
    return self._do_install(consolecb, meter, removeOld, wait)
  File "/usr/lib/pymodules/python2.6/virtinst/Guest.py", line 1038, in _do_install
    "install")
  File "/usr/lib/pymodules/python2.6/virtinst/Guest.py", line 1009, in _create_guest
    dom = self.conn.createLinux(start_xml, 0)
  File "/usr/lib/python2.6/dist-packages/libvirt.py", line 1277, in createLinux
    if ret is None:raise libvirtError('virDomainCreateLinux() failed', conn=self)
libvirtError: internal error Process exited while reading console log output: char device redirected to /dev/pts/1
qemu: could not open disk image /var/lib/libvirt/images/vm-fififi.img: Permission denied

phil@frederic:~$ ls -l /var/lib/libvirt/images/
total 152
drwx------ 2 root root  16384 Sep 29 22:17 lost+found
-rw------- 1 root root 262144 Oct  1 16:45 vm-fififi.img
phil@frederic:~$

It is interesting that virt-install created the virtual disk image, but cannot use it.

Then I used virt-manager to remove the disk image, and re-create it using:

Code:

Name: vm-fififi
Format: qcow2
Max Capacity: 12000MB
Allocation 0 MB

Code:

phil@frederic:~$ ls -l /var/lib/libvirt/images/
total 152
drwx------ 2 root root  16384 Sep 29 22:17 lost+found
-rw------- 1 root root 262144 Oct  1 16:49 vm-fififi.img
phil@frederic:~$

And lo and behold, there it is.

Then I tried a similar virt-install, but assuming an existing virtual disk image:

Code:

phil@frederic:~$ sudo virt-install  --name vm-fififi --ram 512  --disk /var/lib/libvirt/images/vm-fififi.img --cdrom /home/phil/Downloads/ubuntu-12.04.1-server-amd64.iso --vnc --noautoconsole --os-type linux  --network=bridge:br1,mac=52:54:00:a3:88:df


Starting install...
ERROR    internal error Process exited while reading console log output: char device redirected to /dev/pts/1
qemu: could not open disk image /var/lib/libvirt/images/vm-fififi.img: Permission denied

Domain installation does not appear to have been
 successful.  If it was, you can restart your domain
 by running 'virsh start vm-fififi'; otherwise, please
 restart your installation.
ERROR    internal error Process exited while reading console log output: char device redirected to /dev/pts/1
qemu: could not open disk image /var/lib/libvirt/images/vm-fififi.img: Permission denied
Traceback (most recent call last):
  File "/usr/bin/virt-install", line 1033, in <module>
    main()
  File "/usr/bin/virt-install", line 915, in main
    start_time, guest.start_install)
  File "/usr/bin/virt-install", line 957, in do_install
    dom = install_func(conscb, progresscb, wait=(not wait))
  File "/usr/lib/pymodules/python2.6/virtinst/Guest.py", line 973, in start_install
    return self._do_install(consolecb, meter, removeOld, wait)
  File "/usr/lib/pymodules/python2.6/virtinst/Guest.py", line 1038, in _do_install
    "install")
  File "/usr/lib/pymodules/python2.6/virtinst/Guest.py", line 1009, in _create_guest
    dom = self.conn.createLinux(start_xml, 0)
  File "/usr/lib/python2.6/dist-packages/libvirt.py", line 1277, in createLinux
    if ret is None:raise libvirtError('virDomainCreateLinux() failed', conn=self)
libvirtError: internal error Process exited while reading console log output: char device redirected to /dev/pts/1
qemu: could not open disk image /var/lib/libvirt/images/vm-fififi.img: Permission denied

Hmmm... it seems to fail the same way.

Details of my machine are:

Code:

phil@frederic:~$ cat /etc/debian_version 
6.0.6
phil@frederic:~$ sudo libvirtd --version
libvirtd (libvirt) 0.8.3
phil@frederic:~$ sudo virt-install --version
0.500.3
phil@frederic:~$ uname -a
Linux frederic 2.6.32-5-amd64 #1 SMP Sun Sep 23 10:07:46 UTC 2012 x86_64 GNU/Linux
phil@frederic:~$ virt-manager --version
0.8.4

Eventually, I tried changing the permissions on virtual disk image to 666, and re-ran the virt-install (without the "format=qcow2") and that successfully created the virual machine, and kicked off the ubuntu install. But that is not a solution, just a clue.

My questions are:

1) Why can't virt-install use the virtual disk image vm-fififi.img? It is run with sudo, it manages to create the file, so why is it having trouble accessing the file for use?

2) What are the correct owner, group, and permissions for a qcow2 virtual disk file? In my case, the owner and group is root, and the permissions are 600.

3) Why does the install work if I change the permissions on the virtual disk image to 666? I use sudo on the install, so shouldn't that cover permissions problems?

4) I am probably missing something painfully obvious, so the big question is: What am I missing?

Thanks,
Phil

ordinary · 10-02-2012, 04:43 PM

Well, for reasons that are not entirely clear, changing the ownership of the virtual disk image to libvirt-qemu makes it work. Group is still root, and the permissions are 600.

I don't know if this is correct. I did not see a suitable group, so I just left it as root. I'll have to wait and see if it works in the long term.

Onward and upward, I guess.

I am marking this thread solved because the immediate problem was resolved. But the real issue remains: I still don't know why the virt-install command I used don't work.

Thanks,
Phil