2011/7/7 Jay Pipes <jaypi...@gmail.com>: > Multiple zones is currently only supported in the OpenStack API, and > the question has been raised whether effort should be expended to get > parity in the EC2 API for this. The problem with the EC2 API is that > we do not have control over the instance identifiers -- they are an 8 > character text string. We would still need to map the EC2 instance > identifier to some globally unique identifier (like a UUID), but the > solutions for how to do this aren't pretty (see > http://etherpad.openstack.org/EC2UUID).
I don't particularly like the idea of maintaining a mapping table. If such a method is to be guaranteed to function, we need something that can reliably assign EC2-compatible ID's corresponding to the UUID's without collisions. If we can come up with such a method anyway, why use UUID's to begin with? (For the record, I do believe we *can* come up with such a method. I raised this point in one of the (several) disucssions we've had on the subject of ID's, but the ability to assign an unlimited amount of non-colliding ID's perpetually autonomously took precedence) I think the only sensible route is truncating (or by other means reducing) the UUIDs to 32 bits (or revisit (again) the choice of UUID's, of course). With a 32 bit key space, a user with 10000 active objects of the same type (so in the same key space) will have a 1% chance of having colliding ID's. With ~78000 objects, we're at 50%. I guess that's a risk we'll have to live with. The tricky part is figuring out how to handle the collisions when they actually arise. -- Soren Hansen | http://linux2go.dk/ Ubuntu Developer | http://www.ubuntu.com/ OpenStack Developer | http://www.openstack.org/ _______________________________________________ Mailing list: https://launchpad.net/~openstack Post to : openstack@lists.launchpad.net Unsubscribe : https://launchpad.net/~openstack More help : https://help.launchpad.net/ListHelp
