Configuring, Optimizing and Managing the Tomcat Servlet Container on NetWare® 6

Jeff TulleySoftware Engineer, Novell, Inc.jtulley@novell.com

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Presentation Outline

Tomcat on NetWare® 6

ConfiguringOptimizingDeployingManaging

Tomcat on NetWare 6.5ConfiguringOptimizingDeployingManaging

Tomcat on NetWare 6 Philosophy

For Management onlyNot tuned for performance

Not set up like typicalTomcat 3.x

Key Files:sys:/tomcat/33/bin/tomcat33.ncf

sys:/tomcat/33/conf/nwserver.xmlsys:/tomcat/33/conf/nwapps-(context).xmlsys:/tomcat/33/conf/nwworkers.properties

Configuration

Configuration – tomcat33.ncf

Starts up tomcat, using nwserver.xml for configurationDefines classpath of Tomcat• may need to be modified if the webapp

contains native codeActual java command is here, so JVM tuning parameters go here also

Configuration – nwserver.xml

Main configuration file for Tomcat 33Departures from standard server.xml:• Different ports• Different application definition prefix

(nwapps- as opposed to apps-)Ways it didn’t depart• Auto deploy from tomcat/33/webapps

– We should have changed this, in retrospect

Configuration – nwapps-(context).xmlAnything starting with nwapps-, and followed by a context name, defines a context that is not auto deployed from sys:/tomcat/33/webappsFor instance, nwapps-NSearch.xmlDefines the context /NSearch

• Doc base is sys:/NSearchThese files, or a WAR file in webapps, provide easiest way to run on Tomcat 33 on NetWare 6

Configuration – nwworkers.propertiesKey to the Apache / Tomcat interactionConfigures Apache mod_jk.nlm, not Tomcat (Should have been put somewhere else probably)Ports in this file must be in sync with those in nwserver.xmlWorker names here must be in sync with those in sys:/apache/conf/adminsrv.confDefault worker name is “ajp13”

Apache 2 Tomcat / Catalina

4.1x

Ajp 13Port 9010

Apache / Tomcat intercommunication

Optimizing

Tomcat on NetWare 6 was not optimized for heavy usage, since it was targeted for management onlyTuning is necessary for dedicated Servlet Container usage, for instance with

NSearch NPS OnDemand™

Optimizing – philosophy

Key point to remember when tuning Tomcat -every application requires different tuning parameters, there is no “one size fits all”If your server is dedicated to one application, this makes tuning easierIf your server has one type of usage pattern, tuning is easier alsoLike database tuning, this is partly an art, with tradeoffs involved

Optimizing – nwserver.xml parametersThe main parameters that must be tuned are found in nwserver.xml, in the <RequestInterceptor> tag• maxThreads• maxSpareThreads• MinSpareThreads

The SpareThreads settings determine how many threads are kept alive while the system is idle (not under heavy load)Ideal number of threads must be analyzed against memory usage, processing activity of your application, etc.

Optimizing – memory settings

Tomcat33.ncf does not set a maximum heap size

• Default JVM 1.3 max heap is 64MB • Default JVM 1.4 max heap is 128MB • Your applications needs may be way more than either

of these defaultsTo determine your application’s needs:

• Add “-Xmx400m” to beginning of java command• Load test your application for a while• Java –showmemory(id) on tomcat process• Set the max to a value higher than committed heap

Optimizing – more memory settingsNLMS have a limit of about 400 MB allocation sizeSetting the –X flag above that may result in an invalid allocation, giving you only the 64 MB defaultIf you need more than this much memory:

• Use the server –u option– TID # 10072708– Set the value at (total memory – OS memory

requirements), in bytes• Use multiple tomcat instances

Optimizing – multiple tomcats

Create your own ncf files, starting up Tomcat with separate server.xml filesEach listens on a separate AJP portThere is a worker in nwworkers.properties corresponding to each tomcat instanceEach of these workers is in the worker.loadbalancer.balanced_workers listApache will send requests to these workers in a weighted round-robin manner, with sticky sessions

Optimizing – outside of Tomcat

Upgrade to JVM 1.4Upgrade Apache to Apache 2.0

• Apache 2.0 has more caching capabilities• Then you can set the cachesize parameter on each

worker (in nwworkers.properties)• Set it to the same as the number of Apache

threads• Make sure Apache is serving your static content

– In a “purely dynamic” application you still have static image files, sometimes downloadable files, etc.

Deploying – techniques

Three methods to deploy to Tomcat 33• Place a WAR file in sys:/tomcat/33/webapps

– Tomcat automatically explodes it on first execution• Explode WAR into sys:/tomcat/33/webapps• Place your exploded WAR wherever, define its

context name and location in conf/nwapps-(context).xml

It’s that simple

Managing

Management of Tomcat is done completely manually, through

configuration files

See the key files already pointed out in earlier slides.

Tomcat 4 on NetWare Philosophy

We realized that “only for management” didn’t coincide with realityNew philosophy: “separate management”, out of the way of the default Tomcat instanceDefault Tomcat instance has as few changes as necessaryInternal Novell applications (non-admin) play in the same world as 3rd party applications

Configuring – Tomcat 4 User Instance

Key Files:sys:/tomcat/4/bin/tomcat4.ncfsys:/tomcat/4/bin/tc4stop.ncsys:/tomcat/4/bin/catalina.plsys:/tomcat/4/bin/startup.ncfsys:/tomcat/4/conf/server.xml

sys:/apache2/conf/mod_jk/workers.properties

Key Files:Sys:/adminsrv/conf/admin_tomcat.xml

Sys:/system/tcadmup.ncfSys:/system/tcadmdn.ncf

Same workers file

Configuring – Tomcat 4 Admin instance

Configuring – Startup/Shutdown Scriptstomcat4.ncf, tc4stop.ncf:

• Start and stop the user instance, respectivelystartup.ncf:

• Calls into catalina.pl, taking care of some “NetWareisms” of starting up (startup dir)

catalina.pl:• Has all of the smarts. • Akin to catalina.bat• Allowed some functionality not available in NCFs

Configuring – Server.xml

As much as is possible, server.xml is identical to the server.xml downloaded from jakarta.apache.orgWe had to change the following items:

• AJP port change to 9010 (conflict with NetWare Remote Manager port, 8009)

• We disabled the “UserDatabaseRealm”, instead using the “JNDIRealm” for authentication/ authorization against Novell eDirectory™. (more on this later)

• Commented out port 8080, the internal HTTP stack

Configuring – workers.properties

Content has not changed much, just the file locationMakes more sense in apache directoryDefault worker name is the same as the NetWare 6 Tomcat 33 worker (ajp13)Separate worker for admin instance (ajp13_admin)Ports should not conflict with those used on NetWare 6, so Tomcat 4 could work there equally well

Configuring – Admin Instance Files

tcadmup.ncf, tcadmup.ncf:• Start and stop the admin instance, respectively

Admin_tomcat.xml:• Configuration of an instance of Tomcat 4, with

separate ajp ports, also using the JNDIRealm for security, auto-deploying out of sys:/adminsrv/webapps

You shouldn’t have to change these files

Optimizing

Tomcat 4 IS optimized a bit right out of the box

• Max and min threads are set• Memory is optimized a bit

(some maximums are set)• Workers cachesize property is set• Apache 2 is already in place giving

static files speedup

Optimizing – server.xml parametersSame as with Tomcat 33, only the names have changedOn the <Connecter> tag, “CoyoteConnector”, there are the following:

minProcessors

maxProcessors

acceptCount

Optimizing – multiple tomcats

Create your own ncf files, starting up Tomcat with separate server.xml filesEach listens on a separate AJP portThere is a worker in nwworkers.properties corresponding to each tomcat instanceEach of these workers is in the worker.loadbalancer.balanced_workers listApache will send requests to these workers in a weighted round-robin manner, with sticky sessions

Deploying – techniques

1

2

3

Three methods to deploy to Tomcat 4Place a WAR file in sys:/tomcat/4/webapps

• Tomcat automatically explodes it on first executionExplode WAR into sys:/tomcat/4/webappsPlace your exploded WAR wherever, define its context name and location in webapps/ (context).xml

These are identical to Tomcat 33, except last item

Managing

New to Tomcat 4 are the admin and manager apps– /tomcat/admin/

– Ability to manage separate pieces of server.xml in a web-based fashion

– /tomcat/manager/ – Allows you to manage contexts’ life-cycles

» Start» Stop» Restart

Managing - /tomcat/manager/html

Debugging

Java Platform Debugger Architecture is new to JVM 1.4 on NetWaretc4jpda.ncf - starts up Tomcat in debug mode, communicating over socket 9070You can use all standard socket-based JPDA debuggers

• Chances are your favorite java editor supports this

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