Re: Key factors for production readiness of Hedwig

2010-11-10 Thread Patrick Hunt
On Wed, Nov 10, 2010 at 10:58 AM, Erwin Tam  wrote:
> 1. Ops tools including monitoring and administration.

Command port (4 letter words) for monitoring has worked extremely well
for zk. Whatever you do put the command port on a separate port, and
make it a full fledged feature rather than a hack (allow clients to
maintain sessions, allow more complex requests than just a 4letter
word, etc...). Perhaps in today's world you should just go with a REST
interface (easy using jersey) rather than try to implement a
4letterword. json/xml/text for free. easy to integrate with any
monitoring app or adhoc script.

Patrick


Re: Verifying Changes

2010-11-10 Thread Patrick Hunt
Perhaps something similar to what Ben detailed here? (rendezvous)
http://developer.yahoo.com/blogs/hadoop/posts/2009/05/using_zookeeper_to_tame_system/

Change the key, add child znode(s) that's deleted by the "notified"
client(s) once it's read the changed value. Some details need to be
worked out but seems reasonable.

Patrick

On Tue, Nov 9, 2010 at 6:42 PM, Ben Hall  wrote:
> Hi All...
>
> Long time reader... First time writer...  Hehe...
>
> I am curious to know what successes people have had with verifying zookeeper 
> changes across a pool of clients.  I.E. Being able to verify that your 
> changed Key did in fact get pushed out to all of the subscribed clients.
>
> We are looking at creating a hash of the finished key value and comparing 
> that with what is on the ZK server... But curious if anyone has any smarter 
> ideas.
>
> Thanks
> Ben
>


Re: Key factors for production readiness of Hedwig

2010-11-10 Thread Erwin Tam
Thanks for the offer to help Milind!  We've covered most of the things
that are still missing with Hedwig to make it more production ready.  I
mentioned having an engineering team mainly in the context of finding an
internal team here at work to support and develop it.  But we now have
it open sourced so hopefully we can get enough interest in people using
it to work on it.  Here's a list of missing things in Hedwig.

1. Ops tools including monitoring and administration.
2. Cleaner deployment strategies (just have some hacky bash scripts to
do this now).
3. Non-star topologies including logic on forwarding messages between
regions, tools to redefine your topology on the fly (in case a
datacenter region goes down for some reason), topology validation tool
to make sure all regions are connected.
4. Policies on where we can send messages to.  This could be topic based
such as defining a topic containing inclusion/exclusion filters on which
regions it should exist in.  Additionally, perhaps a message level
mechanism for this would be useful.  e.g. expose this to clients so when
they publish messages, they can state where they want the messages to go
to.
5. More testing to find bugs, stress the system, performance tuning,
etc.

Erwin

On Tue, 2010-11-09 at 12:47 -0800, Milind Parikh wrote:

> What are the other features? How can I help? I would love to experiment with
> Hedwig. So I could help, in my spare time , with the documentation. Why
> would you need an engineering team to support it? You have this open
> sourced. Couldn't you use the power of the community?
> 
> As you can see, I am pretty eager to try hedwig.
> 
> Regards
> -- Milind
> 
> 
> On Tue, Nov 9, 2010 at 12:00 PM, Erwin Tam  wrote:
> 
> > Hi Milind, Hedwig is still in prototype phase so it lacks several
> > features to make it production ready.  We are trying to find an
> > engineering team to work on and support it.
> >
> > (a) Monitoring is one of the big missing pieces to make it production
> > ready.  We have some thoughts on it.  The simplest solution would be to
> > use JMX style bindings for monitoring and admin purposes.
> >
> > (b) We have designs on non-star topologies and the underlying pieces to
> > support this are there (version vectors for messages published/consumed
> > in all regions).  This is something we've thought about since the
> > beginning.  However, due to lack of resources, we have not implemented
> > this yet.  There are a few enhancements that we know about and will
> > shortly document them either via a wiki page or open jiras for Hedwig.
> >
> > (c) We are in the process of converting some internal documents we have
> > for Hedwig for third party consumption.  That's a priority since we
> > definitely want people to know quickly what Hedwig is all about (large
> > scale multi-colo guaranteed delivery pub/sub system) and the
> > architecture of it (shared nothing, commodity boxes, ZooKeeper for
> > coordination, Bookkeeper for persistence).  We also want to emphasize
> > that all pieces of Hedwig are modular and you can slot in your own
> > implementation for the various parts.
> >
> > Erwin
> >
> >
> > > From: Milind Parikh 
> > > Reply-To: 
> > > Date: Fri, 5 Nov 2010 20:08:18 -0700
> > > To: 
> > > Subject: Key factors for production readiness of Hedwig
> > >
> > > What are the key factors for production readiness of Hedwig?  I would
> > > really
> > > like to use Hedwig in some major projects; but having a production
> > > readiness
> > > stamp is important. For my perspective:
> > >
> > > (a) Monitoring
> > > (b) Deployment Patterns (non star based)
> > > (c) Documentation
> > >
> > > Regards
> > > -- Milind
> > >
> >
> >
> >