modred team mailing list archive

[Frederic Koehler <fkfire@xxxxxxxxx>]

Hah, my email died, wow...Wonder what happened to it....
Anyway, this is something like what I wrote before:

* CPU time credits can be very roughly estimated by averaging response time.
It's not all _that_ important anyway if nothing is a behemoth task.

* The hub can immediately, upon establishing connection, redirect client to
a server. The server will still have to communicate with hub somewhat, but
it can only send stuff necessarily pertaining to the hub.

* Jobs should probably be many small tasks to avoid the risk of losing a
giant computation (since saving computation state is not
easy/generalizable). Beyond that, sending keep-alive packets is enough to
know when a client dies.


On Mon, Dec 28, 2009 at 6:16 PM, Scott Lawrence <bytbox@xxxxxxxxx> wrote:

> What?
>
> On 12/28/09, Frederic Koehler <fkfire@xxxxxxxxx> wrote:
> > On Mon, Dec 28, 2009 at 12:45 AM, Scott Lawrence <bytbox@xxxxxxxxx>
> wrote:
> >
> >> "What happens when a client disconnects with unfinished work? Is the
> >> work immeditately reassigned, or does the server wait for a specified
> >> period, etc. This could come up quite a lot because some clients will
> >> just disconnect as soon as work they submitted is completed."
> >>
> >> Ouch.  Good question.  Here's one solution: small tasks (expected time
> >> <2 seconds) are always assigned to two or more clients/servers.  If
> >> both disconnect, reassign, if one disconnects, use the other guy's
> >> answer. Large tasks, if a computer stops regularly checking in every 5
> >> or so seconds, give that computer's results to date to another
> >> computer.  So yeah, I think a client should have to make regular
> >> reports to a server.
> >>
> >> Here's another problem: how do we tell how many CPU time credits to
> >> grant a client?  We can't always tell how long a problem should take
> >> beforehand.
> >>
> >> Here's another problem: which computer should handle the clients?  As
> >> I've been thinking about this, there are three types of computers, the
> >> single hub, the various dedicated servers (capable of storing
> >> permanent data), and the clients.  (The hub is necessary - without it,
> >> the performance of the cluster drastically decreases.) So clients
> >> connect to the hub, and then the hub directs all computers.  But the
> >> hub will get overloaded if 100 computers are checking in every 10
> >> seconds to give it more data (and then the hub has to pass this on to
> >> other servers for storage, etc...).  So at some point, the hub needs
> >> to tell the client to talk to the server.  When?
> >>
> >> Who wants to create that prototype?
> >>
> >> On 12/28/09, Scott Lawrence <bytbox@xxxxxxxxx> wrote:
> >> > This is where we start building prototypes. However, just to keep the
> >> > theoretical side going: I disagree about the privacy issue.  Most
> >> > operations that would benefit from the CPU time of a cluster (notice
> >> > I'm not talking about the data storage and reliability benefits, which
> >> > aren't affected by the presence of clients) are not very private.
> >> > Rendering nice screensavers ("Electric Sheep", I think that one's
> >> > called), and hefty data sifting aren't private - who cares about the
> >> > screensavers, and the data is generally public anyway (of course if it
> >> > wasn't, it would be marked so).
> >> >
> >> > Ray tracing and simulation could be more of an issue.  Hypothetical
> >> > situation: Alice is simulating how wind will affect her proprietary
> >> > airplane design.  Naturally, she can't hand off the whole design, or
> >> > even parts of the design, to random client computers.  This is where
> >> > the windows programmer says, "so the client computers can't help
> >> > Alice."  But that's not true - as a bad example, what if the Modred
> >> > hub gave to a client computer 80 types of landing gear, and told the
> >> > computer, not to simulate something, but to solve a general formula
> >> > that could later be used in the computation in a trivial and quick
> >> > way?  If that client is evil, it will learn that Alice's airplane has
> >> > some sort of landing gear.
> >> >
> >> > Somebody needs to create a prototype of a server that can create
> >> > arbitrary problems in some format, so we can all try to trick it.  I
> >> > suggest lisp as the language, but it's up to the implementer.
> >> >
> >> >
> >> > On 12/28/09, Scott Lawrence <bytbox@xxxxxxxxx> wrote:
> >> >> ---------- Forwarded message ----------
> >> >> From: Frederic Koehler <fkfire@xxxxxxxxx>
> >> >> Date: Sun, 27 Dec 2009 23:21:28 -0500
> >> >> Subject: Re: [Modred] Concept stuff
> >> >> To: Scott Lawrence <bytbox@xxxxxxxxx>
> >> >>
> >> >>  * This is sort-of a solution (while obviously less-than-optimal
> >> >> security,
> >> >> some grid-computing stuff does this, like BOINC), however, it turns
> out
> >> >> that
> >> >> this may require custom validation methods - for example, it's normal
> >> for
> >> >> floating point values to be different on different computers, and the
> >> >> same
> >> >> could apply for other computations.
> >> >>  * A malicious client would only need to misbehave on certain
> problems
> >> >> that
> >> >> a malicious user could designate (or recognize obvious fake
> programs),
> >> >> allowing the fake program test to work.
> >> >>     - A better idea would be to randomly reduplicate some
> computations
> >> >> many
> >> >> times - the malicious client wouldn't notice anything, but could
> easily
> >> >> be
> >> >> singled out
> >> >>
> >> >>   * Thirdly is mostly the same thing I wrote before - only
> computations
> >> >> that
> >> >> are said to be totally unimportant privacy wise could benefit from
> >> >> client-side computing.
> >> >>
> >> >> So I really think that client-side computation is only a good idea
> for
> >> >> a
> >> >> small subset of problems (like the type that there already exist
> >> >> massive
> >> >> grid computing solutions for, like SETI@HOME)
> >> >>
> >> >> On Sun, Dec 27, 2009 at 10:57 PM, Scott Lawrence <bytbox@xxxxxxxxx>
> >> >> wrote:
> >> >>
> >> >>> I want clients to be used for computation, and I want maximum
> >> >>> privacy+security given that restriction.  Some ideas:
> >> >>>
> >> >>> With a large network, two computers can perform the same
> computation.
> >> >>> Furthermore, a smart modred hub can give fake problems to clients,
> >> >>> just to make sure that they're operating correctly.  A client that
> >> >>> isn't operating correctly gets cut. (No second chances! A program
> >> >>> could exploit that!)
> >> >>>
> >> >>> If a user specifies a certain bit of data (SSN, for instance) as
> >> >>> highly sensitive, modred should know not to hand off that
> computation
> >> >>> to a client. (If it does by accident, it certainly should never hand
> >> >>> off the data.) privacy++
> >> >>>
> >> >>> In all cases, computations should be anonymous. privacy++
> >> >>>
> >> >>> Other ideas?
> >> >>>
> >> >>>
> >> >>> On 12/27/09, Frederic Koehler <fkfire@xxxxxxxxx> wrote:
> >> >>> > The idea for client-side computation implies that we have
> >> >>> > highly-trusted
> >> >>> > clients... (we know they won't provide invalid answers) Otherwise,
> >> >>> > client-side computation requires verifying answers and so is only
> >> >>> > useful
> >> >>> for
> >> >>> > a few NP-ish problems. In addition (assuming trusted clients).
> >> >>> >
> >> >>> > Also, it means that, since computations can contain sensitive
> data,
> >> >>> > the
> >> >>> > abillity to spread the computation is limited - unless we know the
> >> >>> > computation is not user-sensitive, it can only try to use the
> user's
> >> >>> > client(s). This way we also know that the client has no interest
> in
> >> >>> > sabatoging answers to mess with other users (except to exploit
> >> >>> server-side
> >> >>> > weaknesses, which is inevitable).
> >> >>> >
> >> >>> > On Sat, Dec 26, 2009 at 10:28 PM, Scott Lawrence <
> bytbox@xxxxxxxxx>
> >> >>> wrote:
> >> >>> >
> >> >>> >> Here is what, as I envision it, will make modred unique (and
> hard):
> >> >>> >>
> >> >>> >>  * Support for clients who can come and leave, lending CPU time
> and
> >> >>> >> using CPU time as they choose.  There are some clusters that
> >> >>> >> support
> >> >>> >> this, but not very many.
> >> >>> >>  * Support for computers participating across the internet.  This
> >> >>> >> goes
> >> >>> >> along with the previous part, but remember we need security to
> make
> >> >>> >> this worth anything. This also means that user data could
> >> potentially
> >> >>> >> be passed to untrusted computers - we need a way to prevent this.
> >> >>> >>  * The ability for clients to run on any OS, using perl, python,
> >> >>> >> java,
> >> >>> >> or (on unix systems) C and C++ (servers and the hub will need to
> >> >>> >> run
> >> >>> >> on linux or at least another unix, or a dedicated OS which we may
> >> >>> >> decide to write)
> >> >>> >>  * Modred has great ease of use because it acts as a single
> unified
> >> >>> >> computer - a special client program exists that allows one to log
> >> in,
> >> >>> >> access and edit files, etc...  This is very close to unique -
> >> >>> >> google
> >> >>> >> has it, though
> >> >>> >>
> >> >>> >> Because of that last point, many OS design issues should come up
> >> when
> >> >>> >> we code modred. (I think Freddy pointed this out?) Thus, we have
> a
> >> >>> >> chance to fix flaws in standard unix, incorporating plan 9-type
> >> stuff
> >> >>> >> (google it and read about it - Plan 9 from Bell Labs, the way the
> >> >>> >> future of unix was) while also creating an actually usable user
> >> >>> >> interface. (No offense, but to a newbie non-super-technical user,
> >> >>> >> linux is a bit harsh...)
> >> >>> >>
> >> >>> >> Some implementation questions and ideas:
> >> >>> >>
> >> >>> >>  - how will updates be handled?  Remember we've got 200 computers
> >> >>> >> potentially, some of which might be clients that want to
> >> >>> >> participate
> >> >>> >> in multiple clusters.
> >> >>> >>
> >> >>> >>  - maybe we should have programs not include front ends.
>  Instead,
> >> >>> >> the
> >> >>> >> modred software creates a front-end from the program's self
> >> >>> >> description.  This would enforce a consistent user interface if
> we
> >> >>> >> could implement it well
> >> >>> >>
> >> >>> >>  - how can we keep users from being able to snoop on each others'
> >> >>> >> data?
> >> >>> >>
> >> >>> >> That's just a sample to get people thinking.
> >> >>> >>
> >> >>> >>
> >> >>> >> On 12/26/09, David Tolnay <dtolnay@xxxxxxxxx> wrote:
> >> >>> >> > Before diving in to specifics about the implementation I think
> we
> >> >>> >> > need
> >> >>> >> > to decide how we want modred to be different from (read: better
> >> >>> >> > than)
> >> >>> >> > existing bootable cluster environments. Here is a short list to
> >> >>> >> > check
> >> >>> >> > out:
> >> >>> >> >
> >> >>> >> > Bootable Cluster CD (http://bccd.net/) - folks presented this
> at
> >> >>> >> > SC09
> >> >>> >> > in portland, it was pretty neat stuff. Packed with education /
> >> >>> >> > debugging / visualization features
> >> >>> >> >
> >> >>> >> > Oscar (http://svn.oscar.openclustergroup.org/trac/oscar) -
> very
> >> >>> >> > trivially simple way to transform an existing unix lab into a
> >> >>> >> > cluster
> >> >>> >> > resource
> >> >>> >> >
> >> >>> >> > Lnx-bbc (http://www.lnx-bbc.com/) - includes cowsay!
> >> >>> >> >
> >> >>> >> > Perceus/warewulf (http://www.perceus.org/portal/) - a lot of
> >> other
> >> >>> >> > sites made reference to this, haven't read too much about it
> >> >>> >> >
> >> >>> >> > What specifically do you want to improve over any of these?
> >> >>> >> >
> >> >>> >> >
> >> >>> >> > On 12/25/09, Frederic Koehler <fkfire@xxxxxxxxx> wrote:
> >> >>> >> >>
> >> >>> >> >>
> >> >>> >> >> So, as far as I understand this project, the idea is to build
> >> >>> >> >> both a client library and a program using the library to do
> >> >>> clustering
> >> >>> >> >> stuff, along with matching server/hub foo (the library might
> be
> >> >>> >> >> the
> >> >>> >> >> same
> >> >>> >> >> or
> >> >>> >> >> whatever, not important).
> >> >>> >> >>
> >> >>> >> >> So from this understanding, it seems that the system should
> >> >>> >> >> provide
> >> >>> >> >> some
> >> >>> >> >> basic pseudo-operating system stuff and programs can build on
> >> >>> >> >> that,
> >> >>> >> >> just
> >> >>> >> >> like they would normally build on their local libc/kernel and
> >> >>> >> >> stuff.
> >> >>> >> >>
> >> >>> >> >> So (I sure like the word "so" today...) if we want the type of
> >> >>> general
> >> >>> >> >> os-like stuff it seems their needs to be support for:
> >> >>> >> >>    * A simpe message passing model - abstract away all the
> >> >>> >> >> TCP-foo,
> >> >>> >>  maybe
> >> >>> >> >> use existing foo here (obviously needs fleshing out)
> >> >>> >> >>    * Permanent storage IO (clone the unix write(), read(),
> >> >>> >> >> open()
> >> >>> >> >> and
> >> >>> >> >> sync()
> >> >>> >> >> model,  or maybe just use one of the existing database-ish
> nosql
> >> >>> things
> >> >>> >> >> out
> >> >>> >> >> there)
> >> >>> >> >>            - Unix-ish model - you create your data hunk, say
> you
> >> >>> >> >> want
> >> >>> >> all
> >> >>> >> >> this stuff in it, then after sync() we know it's actually
> >> >>> >> >> somewhere
> >> >>> >> >> written
> >> >>> >> >> on a hard-drive, and other things can read it too
> >> >>> >> >>            - Unless this isn't in fact needed (but I assume it
> >> is)
> >> >>> >> >>            - Also need to figure out if it's filesystem-ish
> foo
> >> >>> >> >> (hierarchial) we want or more relational database-ish stuff
> >> >>> >> >>
> >> >>> >> >>    * A task delegation model - some type of map/reduce-ish
> stuff
> >> >>> >> >>           - Servers have a few built-in computations, and
> client
> >> >>> >> utilizes
> >> >>> >> >> them?
> >> >>> >> >>           - Or more complex, servers run sandboxed
> computational
> >> >>> code?
> >> >>> >> >>    * A security system?
> >> >>> >> >>         - Needs fleshing out
> >> >>> >> >>         - Presumably what the "hub" manages - it's the trusted
> >> >>> >> >> thing
> >> >>> >> >>         - Obviously, not everybody is allowed to use the
> cluster
> >> >>> >> >> for
> >> >>> >> >> computation, not everybody can find out what everybody else is
> >> >>> >> >> doing,
> >> >>> >> etc.
> >> >>> >> >>       - But also, is their a limit on storage, are some things
> >> >>> >> prioritized
> >> >>> >> >> over others, ?
> >> >>> >> >>
> >> >>> >> >> Theroretically, server's are written to provide the io backend
> >> and
> >> >>> >> >> to
> >> >>> >> >> allow
> >> >>> >> >> for task delegation, clients use the api, although hub has
> it's
> >> >>> >> >> work
> >> >>> >> >> cut
> >> >>> >> >> out
> >> >>> >> >> delegating all the file io and figuring out what the state of
> >> that
> >> >>> is.
> >> >>> >> >>
> >> >>> >> >> On top of some mixture of this, one could build a simple
> >> >>> >> >> unix-ish
> >> >>> >> >> pseudo-cli, theroretically, as well as real software.
> >> >>> >> >>
> >> >>> >> >> Anyway, before actually doing anything, people should read
> about
> >> >>> >> >> PVM
> >> >>> >> >> (Parallel Virtual Machine) and the like (maybe also Hadoop and
> >> >>> >> >> other
> >> >>> >> >> foo-ish
> >> >>> >> >> stuff) so Modred isn't just a bad clone of it
> >> >>> >> >>
> >> >>> >> >> Anyway, (yes, twice in a row!), I figured _someone_ had to
> >> respond
> >> >>> >> >> to
> >> >>> >> >> Scott,
> >> >>> >> >> otherwise he'd feel all lonely and sad :P Now he can have a
> warm
> >> >>> fuzzy
> >> >>> >> >> feeling of deep confusion and uncertainty instead :P
> >> >>> >> >>
> >> >>> >> >>
> >> >>> >> >>
> >> >>> >> >> On Fri, Dec 25, 2009 at 11:06 PM, Scott Lawrence
> >> >>> >> >> <bytbox@xxxxxxxxx>
> >> >>> >> wrote:
> >> >>> >> >> > ---------- Forwarded message ----------
> >> >>> >> >> > From: Scott Lawrence <bytbox@xxxxxxxxx>
> >> >>> >> >> > Date: Fri, 25 Dec 2009 19:20:13 -0500
> >> >>> >> >> > Subject: Design Overview
> >> >>> >> >> > To: modred <modred@xxxxxxxxxxxxxxxxxxx>
> >> >>> >> >> >
> >> >>> >> >> > I'm going to assume that everyone understands the basic
> >> concepts
> >> >>> for
> >> >>> >> >> > modred: a set of networked computers (by 'networked' I mean,
> >> >>> they're
> >> >>> >> >> > all on the internet), divided for the sake of discussion
> into
> >> >>> >> >> > three
> >> >>> >> >> > classes: the 'hub' (the dude in charge, who compupters who
> >> >>> >> >> > want
> >> >>> >> >> > to
> >> >>> >> >> > join connect to), the 'servers' (dedicated computers that
> can
> >> be
> >> >>> >> >> > pretty much relied on not to go down, although redundancy is
> >> >>> >> >> > always
> >> >>> >> >> > nice), and the 'clients' (computers that send in requests
> and
> >> >>> >> >> > can
> >> >>> be
> >> >>> >> >> > used for spare CPU cycles.
> >> >>> >> >> >
> >> >>> >> >> > Ok, so much for assumptions... :-)
> >> >>> >> >> >
> >> >>> >> >> > Things *I* think any design should emphasize:
> >> >>> >> >> >  * security.
> >> >>> >> >> >  * relative ease of use, while retaining significant power.
> >> >>> >> >> > Challenging.  In particular, it should be possible to set up
> a
> >> >>> modred
> >> >>> >> >> > network in under an hour, provided the computers are already
> >> set
> >> >>> up.
> >> >>> >> >> >  * along with the previous bullet point, having an interface
> >> >>> >> >> > that
> >> >>> >> >> > lets
> >> >>> >> >> > one use the entire network like a single computer.  This is
> >> sort
> >> >>> >> >> > of
> >> >>> >> >> > like the way google docs works, except the cloud is private
> >> >>> >> >> >  * therefore, it should be a multi-user system with
> >> >>> >> >> > well-designed
> >> >>> >> >> > privileges etc...
> >> >>> >> >> >
> >> >>> >> >> > I'm not going to discuss my implementation ideas, let's hear
> >> >>> >> >> > others
> >> >>> >> >> > first.
> >> >>> >> >> >
> >> >>> >> >> > --
> >> >>> >> >> > Scott Lawrence
> >> >>> >> >> >
> >> >>> >> >> > Webmaster
> >> >>> >> >> > The Blair Robot Project
> >> >>> >> >> > Montgomery Blair High School
> >> >>> >> >> >
> >> >>> >> >> >
> >> >>> >> >> >
> >> >>> >> >> > --
> >> >>> >> >> > Scott Lawrence
> >> >>> >> >> >
> >> >>> >> >> > Webmaster
> >> >>> >> >> > The Blair Robot Project
> >> >>> >> >> > Montgomery Blair High School
> >> >>> >> >> >
> >> >>> >> >>
> >> >>> >> >>
> >> >>> >> >>
> >> >>> >> >> _______________________________________________
> >> >>> >> >>  Mailing list: https://launchpad.net/~modred
> >> >>> >> >>  Post to     : modred@xxxxxxxxxxxxxxxxxxx
> >> >>> >> >>  Unsubscribe : https://launchpad.net/~modred
> >> >>> >> >>  More help   : https://help.launchpad.net/ListHelp
> >> >>> >> >>
> >> >>> >> >>
> >> >>> >> >
> >> >>> >> > _______________________________________________
> >> >>> >> > Mailing list: https://launchpad.net/~modred
> >> >>> >> > Post to     : modred@xxxxxxxxxxxxxxxxxxx
> >> >>> >> > Unsubscribe : https://launchpad.net/~modred
> >> >>> >> > More help   : https://help.launchpad.net/ListHelp
> >> >>> >> >
> >> >>> >>
> >> >>> >>
> >> >>> >> --
> >> >>> >> Scott Lawrence
> >> >>> >>
> >> >>> >> Webmaster
> >> >>> >> The Blair Robot Project
> >> >>> >> Montgomery Blair High School
> >> >>> >>
> >> >>> >> _______________________________________________
> >> >>> >> Mailing list: https://launchpad.net/~modred
> >> >>> >> Post to     : modred@xxxxxxxxxxxxxxxxxxx
> >> >>> >> Unsubscribe : https://launchpad.net/~modred
> >> >>> >> More help   : https://help.launchpad.net/ListHelp
> >> >>> >>
> >> >>> >
> >> >>>
> >> >>>
> >> >>> --
> >> >>> Scott Lawrence
> >> >>>
> >> >>> Webmaster
> >> >>> The Blair Robot Project
> >> >>> Montgomery Blair High School
> >> >>>
> >> >>
> >> >>
> >> >>
> >> >> --
> >> >> Scott Lawrence
> >> >>
> >> >> Webmaster
> >> >> The Blair Robot Project
> >> >> Montgomery Blair High School
> >> >>
> >> >
> >> >
> >> > --
> >> > Scott Lawrence
> >> >
> >> > Webmaster
> >> > The Blair Robot Project
> >> > Montgomery Blair High School
> >> >
> >>
> >>
> >> --
> >> Scott Lawrence
> >>
> >> Webmaster
> >> The Blair Robot Project
> >> Montgomery Blair High School
> >>
> >> _______________________________________________
> >> Mailing list: https://launchpad.net/~modred
> >> Post to     : modred@xxxxxxxxxxxxxxxxxxx
> >> Unsubscribe : https://launchpad.net/~modred
> >> More help   : https://help.launchpad.net/ListHelp
> >>
> >
>
>
> --
> Scott Lawrence
>
> Webmaster
> The Blair Robot Project
> Montgomery Blair High School
>