>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.With a good >zero-copy transfer lib, live migration support can be extended to non-shared >storage, or cross-datacenter. It's a kind ofvalue.
>task = image_api.copy(from_path_or_uri, to_path_or_uri) ># do some other work >copy_task_result = task.wait() +1 looks cool! how about zero-copying? At 2014-04-23 07:21:27,"Jay Pipes" <jaypi...@gmail.com> wrote: >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 >OpenStack-dev@lists.openstack.org >http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
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