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From Steve Loughran <>
Subject Re: Check process on remote host - Can Ant do that ?
Date Fri, 15 Feb 2008 14:34:17 GMT
David Brown wrote:
> Hello Steve, I am subscribed to various MLs such as Ant and Tomcat because I seem to
find something that grabs my interest almost daily. And, the smartfrog link below is no exception.
I went directly to smartfrog and I have been reading avidly for several hours. 

>And, I agree with the rhetoric so far that smartfrog is not arcane but is overwhelming
to the new user because of all the features (reminds me of JMeter). 

>My current gig is a Tomcat/JBoss assessment for a company that is in dire need of performance
tuning and some type of vertical of horizontal scaling 
 >such that their current web app and web service installations can 
scale up to 25k users. I am currently using JMeter for remote 
distributed testing
 > but what I need more are multiple instances of their servlet 
containers (Tomcat & JBoss). JBoss lends it self to multiple instances 
very handily
 >but their current Tomcat 5.5 by what I have seen on the Tomcat ML can 
be problematic to configure and difficult to maintain as a
 >stable multiple instance server. My question is (before I spend a 
gazillion hours working-out the smartfrog examples) can smartfrog help
 > toward creating a computing grid using disparate machines and 
disparate systems of disparate JDKs/JREs and disparate Tomcat versions?

disparate JDKs is trouble. What we like to do in that world is push out 
the right JDK versions, usually by uploading and installing the RPMs. 
That said, as long as you are running java5+, SmartFrog is happy.

The way to view SmartFrog is the components and the runtimes to do large 
cluster systems, but not some nice shrink-wrapped tool to do it for you. 
What we use for big systems is:

- Anubis ( ) so that 
deployed nodes can find each other without a central manager. This is a 
tuple space that notifies peers on a LAN when nodes come and go.

-a special anubisdeployer that deploys work to any machine matching the 

-a CpuMonitor component that runs vmstat to determine current system 
load. This is used to trigger requests new machines, and for machines to 
declare themselves idle, when they can be returned to the pool.

There's a big dynamicwebserver example that installs and runs apache 
httpd on demand; Supporting Tomcat should be similar; its just not (yet) 
something anyone's put together

 >What are the advantages of smartfrog over just using JMeter and 
load-balancing? I read the PDF whitepaper: Globus Toolkit and smartfrog 
but that reading did not lead to anymore confidence.
 > What happened to the day when I had time to read the Loughran/Hatcher 
Ant book and then go-to-work? Please advise, David.

I dont know what happened to time either.

Where things get interesting over basic load balancing is when you 
allocate real/virtual machines on demand. With virtualisation (I'm doing 
stuff with amazon's EC2 farm right now), you really can do interesting 
stuff. There's some VMWare components being done in the Open Source 
repository; demand allocation of VMs followed by configuration of the 
deployed machines. This is both cost effective and agile.

see also:

What I'd recommend you do is
  1. grab today's release, preferably the self-installing JAR or the 
linux RPMs

  2. Get on the smartfrog-users mailing list and discuss what you want 
to do; see if we can't come up with the right combination of things:

3. Pick something small, like database+app server, before going for the 
200+ node server farms.


Steve Loughran        
Author: Ant in Action 

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