Hi Javi Fontán,
I’m using UpenNebula 4.12.1 with Block LVM datastore and I have a similar problem.
I want to share a persistent image between two VMs to set up an Oracle Cluster Filesitem 2.
BTW libvirt support option <shareable/>, for example, a piece of xml config below.
<disk type='block' device='disk'>
<driver name='qemu' type='raw' cache='writeback'/>
<source dev='/var/lib/one//datastores/0/77/disk.1'/>
<target dev='vdb' bus='virtio'/>
<shareable/>
<address type='pci' domain='0x0000' bus='0x02' slot='0x04' function='0x0'/>
</disk>
How I can hack the current OpenNebula version for use option <shareable/> for image?
Maybe possible to add some custom Attributes to image or some other solution?
I tried to edit the libvirt xml config, file: /var/lib/one/vms/<VM_ID>/deployment.0, but after each stop and restarting VM, generates new configs deployment.1, deployment.2 and etc., so that it does not work.
Really for me it is only one way one persistent image with OCFS2 between two VMs.