On Tue, Feb 15, 2011 at 9:30 AM, Dan Prince <dan.pri...@rackspace.com> wrote: > Hi Justin, > > My vote would be to call the table InstanceProperties.
My vote would be to name the model InstanceProperty and the underlying table instance_properties. > Regarding the ability of other services to use the table wouldn't it be > cleaner if services had their own 'properties' tables (like the Glance > registry service does). > > In other words services would have control over their own metadata tables. If > the volume service needs metadata it should have its own table (or DB), etc. Yes, I think that's what I prefer as well, and I think Justin had suggested this as a possible option below. Cheers! jay > Dan > > -----Original Message----- > From: "Justin Santa Barbara" <jus...@fathomdb.com> > Sent: Monday, February 14, 2011 1:29pm > To: openstack@lists.launchpad.net > Subject: [Openstack] Metadata schema design > > _______________________________________________ > Mailing list: https://launchpad.net/~openstack > Post to : openstack@lists.launchpad.net > Unsubscribe : https://launchpad.net/~openstack > More help : https://help.launchpad.net/ListHelp > I've coded support for metadata on instances. This is part of the > CloudServers API, and I needed it for my idea about metadata hints to the > scheduler. > https://code.launchpad.net/~justin-fathomdb/nova/justinsb-metadata/+merge/49490 > > However, Jay Pipes has raised some (very valid) design questions on the > schema. > > I called the table/entity 'Metadata', and it has two main attributes: 'key' > and 'value'. There's a foreign key to Instances, and long term I'd expect > we'd add more foreign keys to other parent entities. I expect only one of > those parent foreign keys would be populated per row. > > Two questions: > > > 1. Are those words too overloaded? Jay suggested (Instance)Properties. > However, then the question arises about the 'core properties' (zone, image, > instance_type for a machine) and why they are not stored in the 'properties' > collection. This is really metadata, and the CloudServers API calls it > metadata. What do people think these should be named? "Metadata"? > "Properties"? "Tags"? > 2. I imagine that Volumes will also have metadata (long term, probably > everything will - networks, images, instance types, network objects). So > should we have one entity/table or multiple entities (one per parent type)? > I like the idea of one entity, because I think it will yield better code > with less code duplication. From a SQL viewpoint, one per parent entity is > probably more normal though. > > > Justin > > > > _______________________________________________ > Mailing list: https://launchpad.net/~openstack > Post to : openstack@lists.launchpad.net > Unsubscribe : https://launchpad.net/~openstack > More help : https://help.launchpad.net/ListHelp > _______________________________________________ Mailing list: https://launchpad.net/~openstack Post to : openstack@lists.launchpad.net Unsubscribe : https://launchpad.net/~openstack More help : https://help.launchpad.net/ListHelp
