[Gluster-devel] The next version of UFO

[Kaleb Keithley]

As it stands right now, there are some problems with our UFO implementation; 1) it’s based on OpenStack Swift-1.4.8 (Essex), which is rapidly becoming obsolete, if it isn’t already; 2) it doesn’t use Keystone, it uses tempauth, which doesn’t scale; 3) the implementation is a heavily patched version of swift — a patch that is so intrusive that will make it very difficult to port UFO to the current version of Swift (1.7.4, Folsom) and later; and 4) fixing performance bugs is hard, we think it'll be easier to fix them if we clean up the implementation first.

Not only is the patch so big that it’s hard to port, but it has been deemed by some to be — essentially — a fork of Swift. Needless to say, we don’t want to maintain a fork in perpetuity, nor do we want to make moving to newer versions hard (because that would be yet another fork), and we want to be good Open Source citizens and not unnecessarily fork things that don’t need to be forked. And theory says if we make porting to new versions simple and easy, then we can minimize the lag between OpenStack’s releases and our own releases of UFO. And if we can make UFO be completely version agnostic when it comes to Swift; then, when new versions of Swift are released, UFO will automatically work with it with no effort on our part.

To that end, we’re working on rewriting UFO. Instead of patching the Swift sources, we’re implementing a set of layered subclasses that contain the UFO functionality outside of Swift per se. This implementation does rely on a patch of code that has been accepted into the Swift 1.7.5 source. It’s referred to it as the constraints-config-backport patch. We’re lobbying the Fedora community to accept the constraints-config-backport patch into the openstack-swift RPMs that they distribute so that we do not have to provide our lightly patched version of Swift in the glusterfs RPMs.

These changes are already on the HEAD of the glusterfs git tree. I have a set of RPMs in an experimental YUM repo at http://repos.fedorapeople.org/repos/kkeithle/glusterfs/XX-ufo/ and instructions for setting up UFO are in my blog article at http://www.gluster.org/2012/11/a-better-ufo-is-coming-soon/

Ultimately we'd like to get buy-in from the community and move toward shipping this new 1.1 implementation of UFO relatively soon. The sooner we ship this — still based on Swift 1.4.8 — the sooner we can roll out the next one, based on Swift 1.7.4 (or later).

So give it a try, let us know what you think. If you have questions, please don't hesitate to ask.

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Kaleb