Re: Avahi support

[Colin Walters <walters verbum org>]

On Thu, Jan 14, 2016, at 06:05 PM, Cosimo Cecchi wrote:

Hi,

 

I have been thinking about avahi support in OSTree; in a deployment where multiple machines on the same local network use the same tree (or set of trees, in case e.g. they use xdg-app to distribute applications), it would be very convenient if data could be shared across the network without the need to download it from the remote every time. I think that other operating systems have similar functionality (e.g. ChromeOS).

 

Does ChromeOS do that?  I know OLPC looked at this.  I have also heard that Facebook is one gigantic ELF binary that they update via bittorrent inside the datacenter (don't have the link handy now).

 

 

Is there any major architectural roadblock that would prevent this from being implemented?

Would this be an interesting feature for upstream OSTree?

 

I'm not sure.  Right now one *could* implement getting content from anywhere on top of the library externally, but in practice there are some nontrivial ergonomics to overcome.  And some stuff like `commitpartial` etc. is currently private to the HTTP fetcher.

 

My intuition here is that let's first get static deltas stable, and then anything else (bittorrent, Avahi) would be in terms of static deltas, which are an easier format to handle externally.  The "data source" would just need to know the commit FROM and commit TO, and just be responsible for gathering those files and handing them offline to ostree, a far simpler proposition.