OpenNebula

Hi,

Ref. feature #1697

The template merge function introduced in revision 60f0d4bf doesn't work as I expected. What it does is actually replace any attribute found in the template. Some attributes are actually vectors that may contains other attributes, and you don't necessarily want the other attributes from the vector to be crushed by the user supplied template.

Here is a typical example of my use case.

I'm enforcing the size of disk images for my VM by explicitly defining the SIZE attribute in my VM template. I prevent my user from modifying the size by setting DISK/SIZE as a restricted attribute. My VM template contains:

<DISK><SIZE>4096</SIZE></DISK>

I want my user to specify the image they want to use when instantiaing a new VM. A user may provide the following extra template to one.template.instantiate:

<DISK><IMAGE_ID>42</IMAGE_ID></DISK>

The current merge function will simply see my user is overriding the DISK attribute, erase the entire DISK vector from my template, and replace it with the user supplied DISK template.

What I expect is the IMAGE_ID attribute to be added to my existing DISK vector (preserving the DISK/SIZE attribute from my template).

My initial proposed version of the merge function in revision 3deeec21 handled the case of merging vector attributes.

I'm attaching a slightly revised patch (similar to 3deeec21) that applies on top of one-4.0 and preserve merging vector attributes. Note the patch as the same limitation when merging template that have multiple vectors of the same name (ex. multiple NIC vector attributes). Since there is no way to determine which vector to merge, the first vector attribute that matched is always used.

Thanks

Simon