Re: Apache Geronimo Principles & Goals

[Matt Hogstrom]

Dain Sundstrom wrote:
Sorry for the late reply.  I have had these notes for days and just keep 
forgetting to post them.  Notes in line...

On Apr 23, 2006, at 8:07 PM, Aaron Mulder wrote:

Apache Geronimo Principles & Goals


=== Principles ===

How about stating these with heading words like "Competitive", 
"Flexiable", and "Just Works" that tie into the Goals section.  This is 
kind of the executive summary...

 * Be competitive with other application servers
 * Be flexible to include exactly what a user wants (lightweight, 
heavyweight,

I know it is the same thing, but I'd state it as "only what a user wants 
and nothing more"

Probably nitpicky but I think only what a user needs.  There could be wierd dependencies that 
include more than a user wants.


   product integration, customized admin tools, etc.).  Make it easy 
to get
   there from the initial download.

flexiable enough to adapt to (almost) any operating environment.  I 
thinking of university environments where 90% of the server install is 
shared and students get their own apps and logs dirs.  Another one is 
ISVs with shared installations for customers.

 * Be the IntelliJ of app servers (it thinks like you do, works like you
   expect, etc.) -- alternately, be the OS X of app servers (easy to 
use and
   even the hard stuff "just works")

I would state this one as "Just Works" or "Simple".  The server should 
work as an average-joe would expect.  If I throw a jar into web-inf/lib 
and restart my web app it should get picked up (it doesn't currently).

Intuitive comes to mind.


=== Goals ===


Flexibility
-----------
Geronimo should meet anyone's needs from very lightweight to very 
heavyweight.
Generally, the distribution option should be:

1) Minimal -- kernel and command-line/script administration tools only
2) Web -- web container and web admin tools
3) J2EE -- certified J2EE stack with web admin tools

4) Installer -- select from the above "canned" solutions and customize
+1...server templates :)

The included tools must make it extremely easy to download and install
additional features (e.g. plugins) to add on to the basic 
distribution.  And,
of course, anyone is free to create more comprehensive distributions by
bundling plugins and distributing the resulting package.

and changing the directory layout.

It should be possible to get an app running and then have "1-click" 
options
to strip down the server to only what that application requires.  It 
should
also be possible to easily replicate a Geronimo installation to another
machine (or to another existing Geronimo installation).  It should 
also be
possible to export an environment to run a J2EE application client in
(ideally, export it as a dynamic Java Web Start configuration so you 
can just
run it on your local PC by clicking a link in the console).

This feature should be available via a utility, so a user can easily add 
a "download a think-client" button to their web application.  I'd also 
add "create an applet" and "create an installer" options.

We should define who we are talking about.  For a single developer the above makes sense.  Are the 
above tools adequate for the user that has 12,000 servers with some minor differences in deployment 
options?


Performance & Scalability
-------------------------
Performance must be comparable to other application servers in key areas.
Geronimo should support clustering of web and EJB components for 
scalability
and fail-over fault tolerance.  Geronimo should work with common hardware
load-balancers.


Integration with load balancers would be a neat add-on.  For instance when a server comes online it 
can interact with the load balancers to accept work / go offline.

>>
Benchmarks should be made available with clear instructions for users to
configure and run them on Geronimo as well as on other application 
servers.
There should be clear performance tuning guidelines, and the performance
tuning options should be extremely accessible (e.g. provide a dashboard-
style page with all the settings to tune a web application in one place
along with recommendations for the various settings).

Benchmarks we create should reflect real world applications.

Application Portability
-----------------------
It should be as easy as possible to port applications to Geronimo, 
meaning:

"to and from Geronimo"

 - reduce the need for Geronimo-specific XML configuration files
 - simplify and minimize required settings in Geronimo-specific XML
   configuration files (e.g. eliminate nested namespaces, provide 
optimized
   file formats for common things like database pools, eliminate 
target names
   in references)
 - Isolate the application classpath from Server internals (Spring, 
logging)
 - Make common but non-standard code work (global JNDI lookups, etc.)
 - Support file layouts, config files, scripts, termininology from other
   popular application servers (or stay as similar as possible)
 - Provide conversion tools to import configurations from other app 
servers

It should be clear when you are using a geronimo specific feature to 
avoid a surprise later.

Some popular J2EE applications should be ported to Geronimo to confirm 
that
the process is as painless as possible.

Geronimo should run on as a many platforms as possible.

Administration & Management
---------------------------
Geronimo should provide command-line, Ant, Maven, and web versions of all
key tools.  This includes tools to:
 - get a list of available plugins
 - download and install plugins
 - deploy/redeploy applications
 - start and stop the server
 - export an application client wrapped in Java Web Start, even including
   auto-generated SSL keys/certs for mutual authentication.

The web console should be at least as function as the BEA WebLogic web
console.  It should make it easy to both configure the server and gather
runtime statistics.  It should make it easy to run a second Geronimo 
instance
on the same machine (using different network ports).  It should be 
possible
to rearrange the console content to suit the user's needs/style, or at 
least
provide breadcrumb-type access to frequently used functions.

It should be possible to set up several Geronimo configurations that 
share
the same core installation files but have their own configuration files,
deployments, etc. similar to WebLogic domains (but not like JBoss which
copies too many JARs into each configuration).

Geronimo should include a Windows Service to run the server.  Ideally, it
would also have a service like BEA Node Manager to start and stop servers
on remote machines.

Geronimo should include scripts or command-line tools that make it 
easy to
perform and/or automate common tasks such as deploying a new database 
pool or
adding a new JMS destination.

Geronimo should provide packaged integration for management tools such 
as MC4J
and JConsole.  It should be easy to construct custom management tools 
using
Geronimo maangement APIs.

Individual plugins should be able to include management plugins that 
fit into
both the console and the command-line tools.  The user should be able to
update the layout and navigation to customize their own experience.


Development Tools
-----------------
In additional the aforementioned tools, Geronimo should provide detailed
integration with popular IDEs including Eclipse, IntelliJ, and 
NetBeans.  The
integration should include starting and stopping the server, 
debugging, and
generating Geronimo deployment plans for application modules.

Geronimo should also include comprehensive XDoclet support.

Geronimo should provide tools to streamline development wherever 
possible,
including things like (note Rails influence):
 - generating persistence classes and simple web screens on top of them
 - populating a database with test data
 - rolling back to a previous version of an application


Developer Experience
--------------------
Geronimo should produce high-quality error message.  Every deployment 
should
be validated according to the relevent specification's rules before 
Geronimo
attempts to configure and run it.  The deploy tool should always display
relevant errors to the user (without additional arguments).

It would be great to create a more robust error-handling system with 
codes
for internationalized messages, linked to a Wiki with discussion and 
reports
from the field on when each error was encountered, how to work around it,
links to related Jira issues & patches, etc.

It should be possible to easily enable performance traces that break 
down the
time spent in each user-provided method (or important Geronimo 
function such as
a persistence operation or JTA commit) over the course of a single
call/transaction.  It's OK if this introduces overhead, so long as it 
produces
usable aggregate information (62% of each call to /myapp/hello spent 
"here").


Documentation
-------------
Geronimo should include comprehensive free documentation, including:
 - Reference for server and application configuration, emphasizing why
   particular settings are important, when you should use them, and 
how you
   decide what to set them to
 - Howto's for writing your first J2EE applications with Geronimo
 - Howto's for advanced server / administration tasks
 - Detailed guides for available plugins

Lots of samples that people can copy and use as a start for their own projects.

Production Integration
----------------------
Geronimo should provide canned integration with popular open source and
commercial products in categories such as:
 - Databases
 - Distributed caching
 - LDAP, single sign-on, & identity management
 - Portals
 - SOAP/XML stacks
 - ESB/JBI/integration tools
 - Scheduling
 - Reporting
 - Web frameworks
 - Debugging/optimization tools
 - Performance testing
 - ISP virtual hosting / control panels
 - Applications (samples, business apps, bug trackers, CI, etc.)
In many cases this will include an actual Geronimo plugin, but for 
some areas
it may only include documentation (how to configure the tool and 
Geronimo to
work together) or code and documentation (if the integration requires 
extensive
customization so a plugin isn't flexible enough).  In any case, the 
package for
each product should include comprehensive documentation.


Updates and Upgrades
--------------------
Geronimo should include a strategy for updating a server in-place to 
the latest
maintenance release, or at least to apply critical fixes.  Ideally, 
this will
not break any existing plugins or applications.

For major new versions of Geronimo, there should be an upgrade tool to 
convert
configuration files, in any cases where Geronimo will not accept 
configuration
files built for the previous version.

I think we should explicitly state we will never support unreleased 
versions (i.e., no upgrade support from unstable builds).

We should also support users for some number of releases.  Given the relative youth of Geronimo some 
fundamental changes are to be expected (changes in schema, etc.) however over time we will disrupt 
our users with subtle changes (configId to moduleId comes to mind :)  We'll need to consider our 
changes as they will have longer term implications.

Just Works
----------
Geronimo is arguable the last to the J2EE table and there is a lot of 
built up knowledge in our users.  We should leverage that knowledge as 
much as possible.  There should be no-surprises and no-docs required.  
In places where we deviate from the defacto standard, we should try to 
make the break obvious and explicit.  The worst are subtle differences 
and they should be avoided.

-dain