User:Mstone/Commentaries/Mass olpc-update

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Mass olpc-update

 m_stone> greebo: note that there's some ability to deploy updates en masse w/
          olpc-update
  greebo> m_stone, practically how does one do that centrally? I can see how to
          do it from the laptop easily enough. Is there any way planned to
          _push_ updates out?
 m_stone> greebo: yes, it's already implemented even. rather, the laptops poll
          for updates but it's the same effect.
  greebo> For a real implementation I was thinking of pointing all laptops to
          our own repo of the sw, and then setting them all to check for
          updates daily and autoupdate. Then we could just put the up to date
          stuff in our repo after we can test locally and control the updates
          somewhat.
 m_stone> greebo: want an explanation of how it works?
  greebo> m_stone, please :)


olpc-update-query

 m_stone> okay. on your laptop is a program called olpc-update-query (
          http://tinyurl.com/64cpbj ). cron and NetworkManagerDispatcher both
          run that periodically: ( http://tinyurl.com/5qcshl ) and (
          http://tinyurl.com/6mahou ). olpc-update-query's job is to rate-limit
          queries. olpc-update-query, when it runs, executes something called
          the theft deterrence protocol.
  greebo> ok. and they see the up to date stuff online, but do they install
          them? I've run the software update app and it requires me to actually
          install the updated apps hence my confusion.


 m_stone> the relevant section for you is the 'update' field of the server
          response. (what's happening here is the client tries to connect back
          to 'http://antitheft.laptop.org/antitheft/1' ( <-- note lack of https
          for ease of dns tricks ) and asks, among other things, for
          instructions on what build to update toward ). the requests include
          the laptop's SN so they can be answered on a per-laptop basis.


Cryptography

   Quozl> m_stone: for a "locked" laptop what antitheft.laptop.org (or alias)
          provides has to be signed.  therefore greebo in using "unlocked"
          laptops will be able to provide updates using an alias.
 m_stone> Quozl: hang on. the response from antitheft.laptop.org is
          cryptographically verified by code here:
          http://dev.laptop.org/git?p=users/cscott/leases;a=tree


 m_stone> at present, this code works with a hardcoded list of keys: (
          http://tinyurl.com/569w3m ). greebo can modify this using mechanisms
          I'll describe in a few minutes. (the OATS key is the relevant one; it
          is threaded through the code from here: ( http://tinyurl.com/6lo5ba
          ). anyhow, if the signature check passes, then olpc-update-query
          invokes 'perform_update' on the data it received. that data include
          both a statement of what build should be installed as well as a
          collection of urls for where to get it.


Proxies

  greebo> right, what if a proxy username and password is required to get out
          to the internet? I have the proxy details in the server, and the
          users get internet browsing once they put their username and password
          into browse. if I put the username and password into the XS once a
          month to allow straight through traffic then that could be a cute way
          to artificially control updates without changing anything on the
          laptop
 m_stone> no support is presently provided (that I know of) for proxying
          configuration. (that might be a good thing to file a bug requesting,
          though we're unlikely to get to it for 8.2.0). however, if you're
          willing to play DNS tricks, then you should be able to configure the
          system so that it's unnecessary and so that it pulls the builds
          directly from the XS. martin wrote some software called xs-rsync to
          make it easier to host builds on the xs. (upgrade-server would work
          fine too but may be a bit more complicated than what you want)
  greebo> yeah cool, I think I'll stick with what I'm thinking which is to
          simply put the username and password into the XS when I want to
          update them, and then leave it open for a day or two to allow for the
          laptops to update


Final questions

  greebo> just to clarify, that is for system updates right? and hence the
          differentiation between the applications update
 m_stone> greebo: yup. (though 8.2.0 has some smarts for application update as
          well)


  greebo> so the laptops would upgrade from 760 to 762 when it comes out
          automatically if connected online?
 m_stone> greebo: they could be made to do that, with some ingenuity. morever,
          the system can be made to preserve itself using the custom-rpms
          setup. _and_ you get to use the rollback buttons if anything goes
          wrong. so basically, since we'd like to make this easier to use and
          since you sound like you might be willing to try it out for us, we
          may be able to help one another out. :)


  greebo> m_stone, just to clarify again,  the xo update script actually
          installs updates to the xo?
 m_stone> the olpc-update-query program will call perform_update which runs the
          same python code that the olpc-update commandline wrapper uses. then
          scott's sugar update-control-panel entry can be used to update
          activities. in 9.1, there should be even better delegation features
          that will make the networking configuration (for updating, anyway)
          much easier.
  greebo> m_stone, cool, let me know what you want me to do. Happy to test
          stuff. I have some pretty complicated networks I'm working in.


  greebo> m_stone, when I run olpc-update-query on my laptop it doesn't do
          anything. When I run it with -v it just sayd questions the antitheft
          url. Is there anything else it should be doing?
 m_stone> I don't think it's supposed to do anything -- most of the time.
          remember that it's intentionally non-deterministic. (though there are
          some arguments that it can receive that might change that?)
          ...basically, the system has its security goals and it strives to
          reach them.

New Information

See cjb's fork of XS-rsync for an easy-to-use update server.

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