OpenNebula

Quick background : I'm writing a TM driver that uses iscsi to store VM images. This TM driver relies on links to the /dev/disk/by-path/ip* tree.
I have the following link structure :
/srv/cloud/1/images/disk.0 -> /dev/disk/by-path/ip-1.2.3.4:3260-iscsi-iqn.1992-08.com.filer:cloudfiler01-lun-0
/dev/disk/by-path/ip-1.2.3.4:3260-iscsi-iqn.1992-08.com.filer:cloudfiler01-lun-0 -> /dev/sdb

Preliminary tests seem to indicate it works. My TM connects to the filer, adds/clones/deletes LUNs efficiently, and manages permissions on said LUNs.

Now, to the issue at hand. What I would like, is the ability to provision images that are "LUNs on a filer".

The problem is that when "oneimage register" is run, the content of the LUN is copied to the disk.

Browsing through the code, it appears that the code responsible for this is OpenNebula::ImageRepository#copy(). This method calls Fileutils.copy(), which, according to documentation will read the content pointed to by a symlink, and write it to a new file.

The Fileutils.copy_entry() method, on the other hand, will actually keep the link.

I'm using the attached patch. I'm aware all this code no longer exists in soon-to-be 2.4, and it's unlikely to be merged in anything, so I'm leaving this here in case someone else needs it.