Open Stack

>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" <jaypipes at 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
>
>
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