[ovirt-devel] discussion: URI format for libvirt metadata

[Dan Kenigsberg]

On Tue, May 27, 2014 at 01:10:22PM -0400, Kobi Ianko wrote:
> Hi All,
> In the upcoming changes we have decided to use the Metadata section of libvirt to store temporary data. (see http://libvirt.org/html/libvirt-libvirt.html#virDomainGetMetadata)
> For that the libvirt api forces us to specify a valid URI.
> 
> I have suggested using the following pattern: 
> "http://ovirt.org/param/param_name"
> 
> pro: it's very simple and straightforward. 
> con: it leads to nowhere and I don't think we should create a web reference for each param.
> 
> I would like to hear other suggestions from you all

According to
http://libvirt.org/html/libvirt-libvirt.html#virDomainSetMetadata
"""
 ... VIR_DOMAIN_METADATA_ELEMENT @metadata must be well-formed XML belonging
 to namespace defined by @uri with local name @key.
"""
so there is no doubt that we must have a properly-defined namespace on the
URI.

Beyond that, lacking a wiki page explaining the the key, means that a
reviewer knows nothing about what is this param, what are its valid
values, or how oVirt is using it.

Nothing makes sure that no one else in oVirt decides to use the
same param for something else.

It is important to explain that the params that you suggest are going to
be used for communication beween Vdsm and MoM, and that this param is a
vm-specific entity. http://ovirt.org/param/name seems like a parameter
of ovirt at large, not the CPU of a particular VM.

Regards,
Dan.