confidential – for information of designated recipient only. copyright terracotta 2006 cluster...

Confidential – for information of designated recipient only. Copyright Terracotta 2006

Cluster Your JVM to SIMPLIFY application architecture

Terracotta, Inc.


Goal of This Session

Learn how TRANSPARENT CLUSTERING works at a high level

An in-depth look at clustering inside OSS stack


Demo

Shared Drawing Editor

Since a picture is worth a thousand words…


Agenda

Why Runtime Clustering

How Runtime Clustering Works

Our Implementation: Terracotta Architecture

Use what you need: OSS on Terracotta


Programming Should Be Fun

The moment of joy:• That’s awesome• I made that happen• Ergo, I’m awesome

• Java used to be fun• Object oriented, built-in GUI, threading,

networking, GC, and a VM• Lets you do awesome stuff


Inevitably, the Real World Intrudes

High-availability & scalability => scale-out

– Scale-out forces externalized object state: stateless programming model

– Alphabet soup of infrastructure development frameworks creep in

» EJB, JMS, JDBC, SOAP, O/R… Ugh. That’s not awesome.


Impact of API-based Clustering

Scale-out solutions rely on Java Serialization

This breaks object identity– Data put into the cache and then read back will fail:– (obj == obj) false

Perturbs the Domain Model – Management of object references using primary keys– "Fake POJOs"

Adds new coding rules– Need to put() changes back - easy to forget– Can’t trust callers outside the caching class to put a top-level object back in

the cache if they edited it

This is not as simple as the Java language can be


Managed Runtimes to the Rescue

Example: Memory Management– Remember malloc() and free(), heap vs. stack– The JVM introduced most developers to garbage collection, but compile-time

used to win– Today, the JVM is faster; it decides what do do at runtime instead of at

compile time» More information available at runtime » “…only 12 times faster than C means you haven't started optimizing” – Doug Lea

Other Java features that make Developers’ lives easier:– Platform-independent thread coordination / locking– Fat / thin locks in Jrockit decided at runtime– Platform specific optimizations


Clustering at Runtime…Stateful Applications: Code Like Your Mom Used to Make

TC lets you cluster Java in a natural fashion– No Serialization– No API No “cluster-aware” code creeping in

The runtime can do it better than you

Byte Code Instrumentation– GETFIELD– PUTFIELD– MONITORENTER;– MONITOREXIT;– Object.wait()– Object.notify()


Terracotta Architecture: Cluster w/o JEE Resources

Capabilities

Heap Level Replication - share almost any object graph

ACID Replication - no new exceptions or error scenarios

Central storage - keeps app state across restarts

Comm. Hub - manage shared object comms w/o multicast or split brain

Virtual Memory - page in objects on demand

Coordination - We have extended our support to wait / notify and other useful tools

Scale-out

App Server

Web App

JVM DSO Libraries

SharedObjects

Terracotta ServerClustering the JVM

Terracotta ServerClustering the JVM

App Server

Web App

JVM DSO Libraries

SharedObjects

App Server

Web App

JVM DSO Libraries

SharedObjects


Common Use-cases

HTTP Session clustering for HA + scalability– Add-a-server capacity– Efficient replication: no serialization, write only deltas and only where needed– no need to tear objects apart into session attributes– no "put-back"-- nothing to remember (and get wrong) at dev time– No zipper-effect from very large sessions

Clustered caches• Write and update cache once, not N-times• Eliminate the 1/N effect• Choose an existing cache implementation or use your own, Terracotta clusters underneath

• Clustered POJOs

• Clustered Spring

• Collaboration / Coordination / Eventing

• Distributed work management

• Shared Memory / Large Virtual Memory

• Fundamentally open-ended• Wherever thread communication across JVMs and an unlimited, efficiently replicated heap is useful


DEMO 2

Geronimo HTTP Session Clustering

Shared JTable (spreadsheet) Inside Geronimo


package demo.jtable;import javax.swing.JFrame;import javax.swing.JScrollPane;import javax.swing.JTable;import javax.swing.table.DefaultTableModel;

class TableDemo extends JFrame {

// Shared object private DefaultTableModel model;

private static Object[][] tableData = { { " 9:00", "", "", ""}, { "10:00", "", "", ""}, { "11:00", "", "", ""}, { "12:00", "", "", ""}, { " 1:00", "", "", ""}, { " 2:00", "", "", ""}, { " 3:00", "", "", ""}, { " 4:00", "", "", ""}, { " 5:00", "", "", ""} }; TableDemo() { super("Table Demo"); setSize(350, 220); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); Object[] header = {"Time", "Room A", "Room B", "Room C"}; model = new DefaultTableModel(tableData, header); JTable schedule = new JTable(model); getContentPane().add(new JScrollPane(schedule), java.awt.BorderLayout.CENTER); } public static void main(String[] args) { new TableDemo().setVisible(true); }}

Entire Swing Application


package demo.jtable;

import javax.swing.table.DefaultTableModel;

public class Roots { // shared root private static final DefaultTableModel model; // … initialization public static DefaultTableModel getModel() { return model; }}

Web Application: Root Declaration


Web Application: Table Rendering

public class Table { private final DefaultTableModel model; // … initialization public String toString() { StringBuffer buf = new StringBuffer(); Vector<Vector<String>> dataVector = this.model.getDataVector(); buf.append("<table border=\"" + this.border + "\">\n");

synchronized (dataVector) { buf.append(" <tr>\n"); for (int i = 0; i < this.model.getColumnCount(); i++) { buf.append(" <th>").append(this.model.getColumnName(i)).append("</th>\n"); } buf.append(" </tr>\n");

for (Iterator<Vector<String>> i = dataVector.iterator(); i.hasNext();) { buf.append(" <tr>\n"); Vector<String> data = i.next(); for (Iterator<String> j = data.iterator(); j.hasNext();) { buf.append(" <td>"); buf.append(j.next()); buf.append("</td>\n"); } buf.append(" </tr>\n"); } }

buf.append("</table>"); return buf.toString(); }}


<%@ page language="java" import="demo.jtable.Roots" pageEncoding="ISO-8859-1"%><%@ page language="java" import="demo.jtable.web.Table"%>

<html> <head> <title>Open Terracotta JTable</title> </head> <body>

<h1>JTable</h1><%

Table table = new Table(Roots.getModel());table.setBorder(1);

%> <%=table%> </body></html>

Web Application: JSP


<terracotta-config> <dso> <server-host>localhost</server-host> <server-port>9510</server-port> <dso-client>

<roots> <root> <field-name>demo.jtable.Main.model</field-name>

<root-name>demo_jtable_model</root-name> </root>

<root> <field-name>demo.jtable.Roots.model</field-name> <root-name>demo_jtable_model</root-name> </root>

</roots>

<included-classes> <include><class-expression>demo..*</class-expression></include> </included-classes> <web-applications> <web-application>Cart</web-application> </web-applications>

</dso-client> </dso>

</terracotta-config>

Configuration File


Stateful Model in a Stateless World

Hub and Spoke as a SPOF?

Field-level changes too chatty?

Networking overhead to clustering?



Hub and Spoke scale the hub

Field-level changes batched

Network overhead runtime optimized



Simple programming model– Clustered code looks, acts, and smells like regular Java– Testable

Scale-out: high-availability AND scalability

Jettison the traditional trade-offs between simplicity, reliability, and scalability

The power of Terracotta makes programming fun-- increases the frequency of moments of joy


Learn more…

http://www.terracotta.org/

http://blog.terracottatech.com/

http://apache.geronimo.com/


Summary

Infrastructure services are the responsibility of the Runtime, not the developer

New API’s and developer frameworks are not the answer

Technology exists to cluster and cache transparently today

Terracotta works in Geronimo (beta), Tomcat, Weblogic, JBoss (beta), WebsphereCE (beta), and standalone Java apps

Coming soon: Jetty (by JavaOne), Glassfish, Websphere

Scale lightweight stacks: Spring, iBATIS, RIFE, Wicket, Struts, OSCache, Ehcache...

confidential – for information of designated recipient only. copyright terracotta 2006 cluster...

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