JBoss-4.2.2 Clustering for High Availability

1. MAKING APP CLUSTER
READY
Presented by
Pratyush Majumdar

2. CONTENTS
 What is Clustering
 Clustering Goals
 Implementation
 Load Balancing Basics
 Clustering jboss AS
 Clustering Web Application
 Demo

3. WHAT IS CLUSTERING
 Clustering allows you to run an application on several parallel servers
(cluster nodes) while providing a single view to application clients.
 Load is distributed across different servers, and even if one or more of
the servers fails, the application is still accessible via the surviving
cluster nodes.
 Clustering is crucial for scalable enterprise applications, as you can
improve performance by adding more nodes to the cluster.
 Clustering is crucial for highly available enterprise applications, as it is
the clustering infrastructure that supports the redundancy needed for
high availability.

4. CLUSTERING GOALS
 No single SPOF (Single Point Of Failure)
 Ability to increase application throughput by adding hardware
(Horizontal Scaling vs Vertical Scaling)
 Fault Tolerant
 Load Balancing

5. IMPLEMENTATION

6. LOAD BALANCING BASICS
 Apache vs Nginx
 Load balancing Algorithms
 Random
 Round Robin
 Weight Based
 Health checks
 Session stickiness vs ip-hash

7. CLUSTERING JBOSS AS (1/2)
 “all” Configuration
 Clustering Support
 Create multiple copies to run several instances on a single machine
 Partition
 The default name is "DefaultPartition". We can use separate names to segregate Development and Production Environment.
 Multicast
 By default JBoss AS uses UDP multicast for most intra-cluster communication.
 Pick a different multicast address for each cluster you run.
 Generally a good multicast address is of the form 239.255.x.y.
 Socket Binding
 Use of IP Address instead of 0.0.0.0
 Requirement of offset in-case of multiple instances on a single machine
 Server Peer ID
 This is needed for JBoss Messaging across clusters
 Changes in server.xml (Access Logger)

8. CLUSTERING JBOSS AS (2/2)
 Command for starting jboss cluster on separate physical severs
 ./run.sh -c node1 -g APPSERVER -u 239.255.100.100 -b 192.168.1.1 -
Djboss.messaging.ServerPeerID=1
 ./run.sh -c node2 -g APPSERVER -u 239.255.100.100 -b 192.168.1.2 -
Djboss.messaging.ServerPeerID=2
 Command for starting jboss cluster on a single physical sever
 ./run.sh -c node1 -g APPSERVER -u 239.255.100.100 -b 0.0.0.0 -
Djboss.messaging.ServerPeerID=1 -Djboss.service.binding.set=ports-01
 ./run.sh -c node2 -g APPSERVER -u 239.255.100.100 -b 0.0.0.0 -
Djboss.messaging.ServerPeerID=2 -Djboss.service.binding.set=ports-02

9. CLUSTERING APPLICATION
 Dos
 Add <distributable/> tag in web.xml
 Serialize all http session beans
 Implement Quartz Cluster Scheduler
 Using a third party cache provider (EHCache+RMI) to minimize database hits
 Application should be deployable on “touch” of web.xml similarly should get un-deploy
on renaming it to .bak
 Don'ts
 Avoid using static maps, get data from database when required
 Avoid using I/O operations (document upload) otherwise use a common repository
 Avoid using Application Context unless its read-only
 Avoid using complex object in http session to keep replication state minimal
 Synchronization block in code will no longer work

10. DEMO
 Configuring Nginx
 Configuring jboss server
 Joining Cluster
 Application deployment
 Failover Demo

11. QUESTIONS?