Hi Vincent, Zhi, Huiba, sorry for delayed response. See comments inline. On Tue, 2014-04-22 at 10:59 +0800, Sheng Bo Hou wrote: > I actually support the idea Huiba has proposed, and I am thinking of > how to optimize the large data transfer(for example, 100G in a short > time) as well. > I registered two blueprints in nova-specs, one is for an image upload > plug-in to upload the image to > glance(https://review.openstack.org/#/c/84671/), the other is a data > transfer plug-in(https://review.openstack.org/#/c/87207/) for data > migration among nova nodes. I would like to see other transfer > protocols, like FTP, bitTorrent, p2p, etc, implemented for data > transfer in OpenStack besides HTTP. > > Data transfer may have many use cases. I summarize them into two > catalogs. Please feel free to comment on it. > 1. The machines are located in one network, e.g. one domain, one > cluster, etc. The characteristic is the machines can access each other > directly via the IP addresses(VPN is beyond consideration). In this > case, data can be transferred via iSCSI, NFS, and definitive zero-copy > as Zhiyan mentioned. > 2. The machines are located in different networks, e.g. two data > centers, two firewalls, etc. The characteristic is the machines can > not access each other directly via the IP addresses(VPN is beyond > consideration). The machines are isolated, so they can not be > connected with iSCSI, NFS, etc. In this case, data have to go via the > protocols, like HTTP, FTP, p2p, etc. I am not sure whether zero-copy > can work for this case. Zhiyan, please help me with this doubt. > > I guess for data transfer, including image downloading, image > uploading, live migration, etc, OpenStack needs to taken into account > the above two catalogs for data transfer.
For live migration, we use shared storage so I don't think it's quite the same as getting/putting image bits from/to arbitrary locations. > It is hard to say that one protocol is better than another, and one > approach prevails another(BitTorrent is very cool, but if there is > only one source and only one target, it would not be that faster than > a direct FTP). The key is the use > case(FYI:http://amigotechnotes.wordpress.com/2013/12/23/file-transmission-with-different-sharing-solution-on-nas/). Right, a good solution would allow for some flexibility via multiple transfer drivers. > Jay Pipes has suggested we figure out a blueprint for a separate > library dedicated to the data(byte) transfer, which may be put in oslo > and used by any projects in need (Hoping Jay can come in:-)). Huiba, > Zhiyan, everyone else, do you think we come up with a blueprint about > the data transfer in oslo can work? Yes, so I believe the most appropriate solution is to create a library -- in oslo or a standalone library like taskflow -- that would offer a simple byte streaming library that could be used by nova.image to expose a neat and clean task-based API. Right now, there is a bunch of random image transfer code spread throughout nova.image and in each of the virt drivers there seems to be different re-implementations of similar functionality. I propose we clean all that up and have nova.image expose an API so that a virt driver could do something like this: from nova.image import api as image_api ... task = image_api.copy(from_path_or_uri, to_path_or_uri) # do some other work copy_task_result = task.wait() Within nova.image.api.copy(), we would use the aforementioned transfer library to move the image bits from the source to the destination using the most appropriate method. Best, -jay _______________________________________________ OpenStack-dev mailing list [email protected] http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
