Hi list, suppose I have an immutable (ie: due to a read-only snapshot) backing file. After creating an overlay file with "qemu-img create -f qcow2 -o backing_file=/path/to/immutable/file.img current.qcow2", libvirt refuse to start the virtual machine and exits with an error stating "Could not open backing file /path/to/immutable/file.img: Permission denied". From my understanding, libvirtd is trying to change the owner/permissions/selinux context of the backing file but, being it immutable, fails to start the VM. Is that the expected behavior? Thanks. -- Danti Gionatan Supporto Tecnico Assyoma S.r.l. - www.assyoma.it email: g.danti at assyoma.it - info at assyoma.it GPG public key ID: FF5F32A8
Il 03-09-2018 13:14 Gionatan Danti ha scritto:> Hi list, > suppose I have an immutable (ie: due to a read-only snapshot) backing > file. > > After creating an overlay file with "qemu-img create -f qcow2 -o > backing_file=/path/to/immutable/file.img current.qcow2", libvirt > refuse to start the virtual machine and exits with an error stating > "Could not open backing file /path/to/immutable/file.img: Permission > denied". > > From my understanding, libvirtd is trying to change the > owner/permissions/selinux context of the backing file but, being it > immutable, fails to start the VM. Is that the expected behavior? > > Thanks.Hi all, any suggestion on the matter? Thanks. -- Danti Gionatan Supporto Tecnico Assyoma S.r.l. - www.assyoma.it email: g.danti at assyoma.it - info at assyoma.it GPG public key ID: FF5F32A8
On Tue, Sep 04, 2018 at 17:32:49 +0200, Gionatan Danti wrote:> Il 03-09-2018 13:14 Gionatan Danti ha scritto: > > Hi list, > > suppose I have an immutable (ie: due to a read-only snapshot) backing > > file. > > > > After creating an overlay file with "qemu-img create -f qcow2 -o > > backing_file=/path/to/immutable/file.img current.qcow2", libvirt > > refuse to start the virtual machine and exits with an error stating > > "Could not open backing file /path/to/immutable/file.img: Permission > > denied". > > > > From my understanding, libvirtd is trying to change the > > owner/permissions/selinux context of the backing file but, being it > > immutable, fails to start the VM. Is that the expected behavior? > > > > Thanks. > > Hi all, any suggestion on the matter?You forgot to specify the format of the backing file into the overlay file (qemu-img option -F). Libvirt treats any unspecified format as raw since it's not secure to do probing of the format.