Comment 0 for bug 1562845

For some reason virt-manager (or libvirt) is trying to change the *ownership* of the ISO file I'm using to install ubuntu. That ISO file is perfectly readable by the libvirt-qemu user:

$ sudo -u libvirt-qemu -H ls -lah /mybook/downloads/isos/ubuntu/16.04/ubuntu-16.04-beta2-desktop-amd64.iso
[sudo] password for andreas:
-rw-rw-r-- 1 andreas andreas 1.5G Mar 23 05:45 /mybook/downloads/isos/ubuntu/16.04/ubuntu-16.04-beta2-desktop-amd64.iso

$ sudo -u libvirt-qemu -H file /mybook/downloads/isos/ubuntu/16.04/ubuntu-16.04-beta2-desktop-amd64.iso
/mybook/downloads/isos/ubuntu/16.04/ubuntu-16.04-beta2-desktop-amd64.iso: DOS/MBR boot sector ISO 9660 CD-ROM filesystem data (DOS/MBR boot sector) 'Ubuntu 16.04 LTS amd64' (bootable); partition 2 : ID=0xef, start-CHS (0x3ff,254,63), end-CHS (0x3ff,254,63), startsector 3071200, 4736 sectors

That file is in a remote CIFS share, mounted at mybook:
$ mount|grep mybook
//mybook/Public on /mybook type cifs (rw,relatime,vers=1.0,cache=strict,username=andreas,domain=MYBOOK,uid=1000,forceuid,gid=0,noforcegid,addr=10.0.10.176,unix,posixpaths,serverino,mapposix,acl,rsize=61440,wsize=65536,actimeo=1,user=andreas)

virt-manager crashes like this:
Error starting domain: unable to set user and group to '125:138' on '/mybook/downloads/isos/ubuntu/16.04/ubuntu-16.04-beta2-desktop-amd64.iso': Permission denied

Traceback (most recent call last):
  File "/usr/share/virt-manager/virtManager/asyncjob.py", line 90, in cb_wrapper
    callback(asyncjob, *args, **kwargs)
  File "/usr/share/virt-manager/virtManager/asyncjob.py", line 126, in tmpcb
    callback(*args, **kwargs)
  File "/usr/share/virt-manager/virtManager/libvirtobject.py", line 83, in newfn
    ret = fn(self, *args, **kwargs)
  File "/usr/share/virt-manager/virtManager/domain.py", line 1402, in startup
    self._backend.create()
  File "/usr/lib/python2.7/dist-packages/libvirt.py", line 1035, in create
    if ret == -1: raise libvirtError ('virDomainCreate() failed', dom=self)
libvirtError: unable to set user and group to '125:138' on '/mybook/downloads/isos/ubuntu/16.04/ubuntu-16.04-beta2-desktop-amd64.iso': Permission denied

The workaround is to copy the ISO file from my NAS to my laptop, perform the install, then delete said ISO file.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: virt-manager 1:1.3.2-0ubuntu2
ProcVersionSignature: Ubuntu 4.4.0-15.31-generic 4.4.6
Uname: Linux 4.4.0-15-generic x86_64
NonfreeKernelModules: zfs zunicode zcommon znvpair zavl
ApportVersion: 2.20-0ubuntu3
Architecture: amd64
CurrentDesktop: Unity
Date: Mon Mar 28 09:36:30 2016
InstallationDate: Installed on 2015-10-03 (176 days ago)
InstallationMedia: Ubuntu 15.04 "Vivid Vervet" - Release amd64 (20150422)
PackageArchitecture: all
SourcePackage: virt-manager
UpgradeStatus: Upgraded to xenial on 2016-03-06 (21 days ago)