On Thu, Sep 06, 2018 at 18:23:46 +0200, Gionatan Danti wrote:
Il 06-09-2018 12:54 Peter Krempa ha scritto:
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.
Hi, the immutable base file *was* a raw image. Then a qcow2 overlay was added, but the vm (which accesses the overlay file) only boot if the base file is writable.
I suspect this is a permission problem. The backing file still needs to be accessed by the VM so libvirt should correctly relabel it (if possible) if the dynamic_ownership feature is enabled. Since you are seeing problems it's possible that libvirt's treatment was not enough. Libvirt's labelling e.g. does not ensure that the directory user/group/label are correct, we only deal with the image. As the messages you've shared have obfuscated paths I can't tell you if that might be a problem. If you are sure that the paths are accessible by the qemu process and it still does not work, please attach debug logs and the XML file to a bug report.
It would surprise me if a read-only raw image + qcow2 overlay is an unsupported configuration, so I feel I am missing something...
No, that is a supported configuration and even the security should not create a problem here as we assume the backing image is raw in this case. That is only a problem if you have a qcow2 image as the base image.
Thanks.
-- Danti Gionatan Supporto Tecnico Assyoma S.r.l. - www.assyoma.it email: g.danti@assyoma.it - info@assyoma.it GPG public key ID: FF5F32A8