Well, if this application is buggy, it is buggy. Either you fix it, or you
use another one. Take xPetstore: Sun says it contains the best j2EE
patterns. Take a subset of this app, cluster it, and you end-up with a
clustered j2eE app.
Good luck,
Sacha
> -----Original Message-----
> From: Joao Clemente [mailto:[EMAIL PROTECTED]
> Sent: vendredi, 4. juillet 2003 01:41
> To: [EMAIL PROTECTED]
> Cc: [EMAIL PROTECTED]
> Subject: Problem after problem... (Re: [JBoss-user] http
> session clustering)
>
>
>
> sorry for replying so late, but here goes:
> No, my problems are still not solved... And I almost gave up
> on this...
> This is my university thesis, and I'm already almost a year
> late (it should
> take a year and I've started my research almost two years
> ago). If this is
> not finished in the 2 year-time, the thesis will be cancelled by the
> university.
>
> I'm suposed to use JBoss to provide a "scalable, fault-tolerant and
> high-available middleware" infra-structure for a j2ee app
> that is being
> developed by another person.. another thesis that is being
> developed at the
> same time, a kind of a webmail on steroids..
> This j2ee application is build on top of a already developed
> open source
> webapplication (servlet+jsp). It was "redesigned" to use
> EJB's aswell. Then
> it was expanded with the help of a couple of more external
> libraries of
> other independent open-source projects..
> So we're talking about a webapp that was redisegned to be a
> j2ee app, and
> then glued to some other libs and projects and with some extra code
> developed here... Put a Ldap connection here, a jabber server there, a
> mailserver somewhere else and with a bit of luck you get
> something like
> this...
>
> About 10 months ago, I should had delivered tested results on
> how the jboss
> cluster can improve the scalability and fault-tolerance of
> this application.
> I'm failing miserably every test I make... day after day I crash into
> another problem, and I'm unable to get those test results...
>
> I'm not saying this is JBoss's fault... No. I've found a
> couple of bugs that
> were JBoss and Javagroups related, as you (sacha) can
> certainly remember.
> But those were not the reasons I'm failing every time I try...
>
> This app sucks. Thats the truth I'm already seeing for a long
> time ago and
> it's exactly that that my thesis advisor (togheter with the
> other theses
> developer and advisor) is refusing to see..
> Sure.. "but the app works fine", they say.
> "It's a problem on your side", they say...
> "It's your work to get that thing usable under load, it's
> what your research
> is suposed to do", they say..
>
> And, actually, if we use 1 (ONE!!!) client (wich, btw, must be
> InterntExplorer) , with 1 (A SINGLE ONE!!!) jboss server, and
> you test it
> manually... it works..
>
> But, for instance,
> - The app uses non-serializable objects all over the http
> session. This
> ceartainly gives us a hard time getting fault-tolerance (or
> failover) to
> work, besides the problems with the load-balancing...
> - The owner of the original project (the one that was
> redesigned here to
> have ejb's besides servlets and jsp's) admitted that it never
> tought of it
> to be clustered, and had no ideia of what was to be done for it to be
> runnable in a cluster...
>
> About three or four months ago I started writing java test
> programs using
> httpunit to load the app.. I've designed a simple client
> model that would
> just do four or five steps in the web app... Simple, right?
> Then added a
> threading model so I could have n similar clients accessing
> the webapp...
> Again, simple...
> I decided to test WITHOUT a cluster. So, there as been at
> least 3 months
> that I do NOT have a load balancer, i DO NOT have a clustered
> jboss setup,
> there is just 1 jboss server and my client application...
>
> Results? I'm almost willing to wait 'till the 2 years of my
> thesis end, my
> university cancels it, so that I can start something new from
> the scratch...
> With NO cluster involved:
>
> - with 1 client ,if I run my test case (get hompage, login,
> check mail,
> logout) for 6 times, I would get locked. End of story.
> - with 2 clients, would get about the same results..
> - with 4 clients, I would get little more than exceptions...
>
> oh, btw, in most of these cenarios, I' would not even be
> able to use the
> application manually, as it would enter a cicle redirecting
> me for the start
> page (it's a "feature" of this app: if something goes wrong
> then redirect to
> start page)... until I shutted down jboss and started it over
> (trying to
> undeploy the app would lock jboss)
>
> and no, it does not stop here...
> after some time, we found out that a singleton object of
> that j2ee app was
> unable to be runned concurrently and would cause the exception...
> gimme some more headaches, and we find out that the locking
> was due to one
> of the external libs that were being used that, by some
> reason, locks under
> yet to be understood circuntances.. oh, and that lib was now
> deprecated..
>
> ok, now what?
> sending mail would work fine if used with InternetExplorer,
> but would give
> my java test client a error 500 page... Now what? Is it my
> client's code
> fault? Whose fault is it? Once again, one more week goes by
> and we find that
> there is another lib that was badly written..
>
> At what point am I now? This app finally runs with 4
> (FOUR!?!) concurrent
> clients... More than that and I get exceptions all over
> again... Gimme a
> break... I know JBoss is useable with hundrends of clients. I
> know it! I see
> it with my own short j2ee apps that I wrote for testing with
> my clustered
> setup!
> This app, with a "no-cluster" environment breaks with 5
> clients! It's
> impossible to but this in a cluster and make it work
> better... it sucks,
> period!
>
>
> But time keeps running and my thesis, my "scalable and fault-tolerant
> middleware for a j2e appp" is going down the drain... no way
> this app is
> going to be useable under load... and I keep banging my head
> on the wall
> each time I run my tests, see the exceptions, and think to my
> self... "ok...
> where is it now? is it my test code? is it the app? is is the
> xyz lib that
> the app uses? maybe it's the foo lib... maybe the mail server
> fault? maybe
> jboss this time? maybe this java vm implementation has a bug... maybe
> the..."
>
>
> sometimes I'm over a week or two without doing progress... I
> wake up in the
> morning, I just feel like crying and I think "why tha hell
> didn't I went for
> medicine school? what 'tha heck... maybe I can still be a plumber or
> something... maybe I should just be in bed..."
>
>
> ----- Original Message -----
> From: "Sacha Labourey" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
> Sent: Sunday, June 08, 2003 5:22 AM
> Subject: RE: [JBoss-user] http session clustering
>
>
> > You're problem is still not resolved Joao?!?
> >
> > > -----Original Message-----
> > > From: [EMAIL PROTECTED]
> > > [mailto:[EMAIL PROTECTED] On Behalf Of
> > > Joao Clemente
> > > Sent: vendredi, 6. juin 2003 14:48
> > > To: [EMAIL PROTECTED]; [EMAIL PROTECTED]
> > > Subject: Re: [JBoss-user] http session clustering
> > >
> > >
> > >
> > > ----- Original Message -----
> > > From: "Stefano Maestri" <[EMAIL PROTECTED]>
> > > To: <[EMAIL PROTECTED]>
> > > Sent: Friday, June 06, 2003 10:44 AM
> > > Subject: Re: [JBoss-user] http session clustering
> > >
> > >
> > > > Thanks, it works.
> > > > just a suggestion add this on your very good "JBoss
> > > Clustering" docs.
> > > > And another thing: I read in jbossbook3.2.1 draft docs in
> > > chapter "Using
> > > > Clustering with Tomcat" this phrase:
> > > > "If you are using a load balancer, make sure that your
> > > setup uses sticky
> > > > session".
> > > > I'm agree that's better to use it to reduce the overload on
> > > JBoss, but it
> > > is
> > > > not necessary. Isn't it?
> > > > BTW we are using since 2 year LVS (LinuxVirtualServer) as
> > > load balancer
> > > with
> > > > JBoss, are you interested in my experience to integrate
> > > something about
> > > LVS
> > > > in your docs exactly as you did for apache?
> > >
> > >
> > > At least I am! I am trying to get that setup working
> correctly for an
> > > entreprise app for over a year now..
> > > This is my unversisty final work, and it has been delayed
> > > forever as I'm
> > > being unable to locate all the changes I need to do to
> get my app with
> > > fault-tolerance features...
> > > Every time I need to recover sessions (in particular http
> > > session) I have a
> > > really hard time 'till I find out where all those exceptions
> > > come from...
> > > I think the problem lies deep inside the app I'm using: It
> > > uses some objects
> > > kept inside the http session that are not serializable and
> > > therefore there
> > > is a need to recover them in a application level..
> > > In particular, I also setup a LVS with LVS-DR (I once had it
> > > with LVS-NAT)
> > > and in the end I had to enable persistence so that each user
> > > session sticks
> > > with a single server...
> > > So, if you had some approach for the problems found
> during the cluster
> > > setup, I would love to hear it...
>
>
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