On Tue, Apr 15, 2008 at 11:31:32AM -0700, Ryan Scott wrote:
I'd like to get some comments on the following...
We would like to use libvirt to store some properties related to a domain. This can be done by adding a simple get/set API as follows:
What are the properties ? I'm not really very enthusiastic about the idea of adding API / XML for generic key,value properties. I think it will quickly be abused as a way to add arbitrary, non-standardized hypervisor / driver specific configuration which would be better represented with explicit schema.
/* * Domain property get/set interfaces * * For GetProp, the return value must be freed by the caller. */ char * virDomainGetProp (virDomainPtr domain, const char *propName);
int virDomainSetProp (virDomainPtr domain, const char *propName, const char *value);
The XML would look something like this:
virsh # dumpxml solaris-pv-0 <domain type='xen' id='-1'> [ snip ] <properties> <blah value="3"/> <foo value="bar"/> </properties> </domain>
One of the key ideas behind libvirt is that we try to provide a consistent set of configuration options across all drivers. NB, I'm not saying we need the lowest-common denominator - just that we try to formalize a way to represent every configuration option in such a away that it could be applied to any driver. I don't think simple key,value pairs are sufficient in the general case. As an example, you could define a property 'console' which takes a pty path as its value. But if you want to generalize this to different types of console access, then a single value becomes insufficient.eg need a host+port for a console accessed over TCP. The more explicit specialized <console> tag allows us the flexibility of adding attributes and sub-elements as needed, not restricting ourselves to key,value pairs. Dan, -- |: Red Hat, Engineering, Boston -o- http://people.redhat.com/berrange/ :| |: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|