[hobbit] Future of Hobbit

Josh Luthman josh at imaginenetworksllc.com
Fri Jan 25 21:01:38 CET 2008


I too have been victim of the rampant recreation of scp.  It makes things
very irritating to work with.  If you've used Windows as a desktop and
things slow down it has a similar feel to it - nice and laggy.

I like the idea of SSL, good one Charles =)

On 1/25/08, Charles Jones <jonescr at cisco.com> wrote:
>
> I think Henriks stance on having the server collect data via ssh
> connections just doesn't scale.  Sure it works fine for a few dozen
> hosts, but let's say you have 2000 servers...now you are expecting be
> able to make 2000 trouble-free ssh connections before the next polling
> cycle begins. This introduces many problems:
>
> * How many ssh sessions can you run at the same time without spiking the
> load on the hobbit server?
> * What happens when an ssh session hangs (could hang the hobbit server,
> or make the poll cycle take too long)
>
> You do know about the "pulldata" option?  It allows the Hobbit server to
> do a "pull" instead of waiting for client "push". This works fairly
> well, and I am using it in a production environment. I can see how it
> would not scale to well either though, for a really large number of hosts.
>
> To picture the scalability, imagine a server that only has to receive
> updates from hobbit clients. All it has to do is listen on port 1984,
> and using relatively little CPU it can probably handle a constant flow
> of client updates.
>
> Now imagine a server that has to go and fetch the client data itself.
> There is a LOT more overhead and processing involved in launching an
> outgoing ssh connection, running a remote client data-gathering command,
> waiting for the output, etc. Imagine 2000 of those firing off every 5
> minutes. How many simultaneous ssh sessions can your server handle?
> I've seen a server brought to its knees by a script that ran amok and
> was doing 50 simulataneous scp commands :)  Some time saving is done by
> using msgcache (no waiting for the data-gathering), but there is still
> the overhead of ssh itself, and having key-based ssh ability could be
> deemed a security risk (anyone who hacks into the hobbit server could
> then ssh to all of your client machines without a password).
>
> A good solution would be an ssl-encrypted, bi-directional protocol. This
> would allow secure transfer of client data, either push or pull, without
> the overhead, management, and security risks of using ssh.
>
> In the meantime, definitely check out the pulldata+msgcache option, as
> it sounds like it will do what you want.
>
> -Charles
>
> Tim Rotunda wrote:
> > To answer Axel's what is it question.....its a Hobbit version of
> BB-Central,
> > which runs on a central server like hobbit does.  It reaches out to the
> > clients via ssh (or whatever) and collects data.  I did a shell script
> > version a few years ago and it worked good until the client count topped
> > 25-30.  Then I migrated it to C and it would handle 60+ nodes pretty
> well.
> > Then I migrated that to a multi-threaded C process and it really
> smoked.  I
> > never did reach the limit with that version.  I think they are still
> using
> > it and adding nodes to the client list, which is prob over 250 or so.
> >
> > I was going to put it out to the community but my company would not
> allow it
> > (idiots) so I couldn't.  I now work only 40 hours a week so now I have
> some
> > time to myself and was thinking about rewriting it from memory and
> putting
> > it out there.  I would put out the one that is threaded and it would
> prob
> > just be for x86 Linux, which should build on Solaris, HP-UX, etc.
> >
>
>
> To unsubscribe from the hobbit list, send an e-mail to
> hobbit-unsubscribe at hswn.dk
>
>
>


-- 
Josh Luthman
Office: 937-552-2340
Direct: 937-552-2343
1100 Wayne St
Suite 1337
Troy, OH 45373

Those who don't understand UNIX are condemned to reinvent it, poorly.
--- Henry Spencer
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