Book Image

JBoss EAP6 High Availability

By : Weinan Li
Book Image

JBoss EAP6 High Availability

By: Weinan Li

Overview of this book

High availability is a system design approach and associated service implementation which ensures that a prearranged level of operational performance will be met during a contractual measurement period. High availability is usually a system combined with many different components that achieve different goals. High availability cluster implementations attempt to build redundancy into a cluster to eliminate single points of failure. JBoss EAP6 High Availability is the perfect guide for learning how to apply the newest technologies provided by JBoss to build your high availability system. With a clear explanation of the design of JBoss EAP6 and its clustering components, this book will help you customize each component to fulfill your specific requirements. Throughout the course of this book, you will learn how to build high availability clusters using the projects provided by JBoss. The book begins with an introduction to the design of JBoss EAP6 and its uses. The next step will be to explore the two companion open source projects - mod_jk and mod_cluster. In this section, you will get to grips with the concept of load balancing with mod_jk and mod_cluster. You will also learn how to enable SSL in the clustering environment and how to configure session replication between EAP6 servers. Furthermore, the appendix section introduces you to some troubleshooting techniques for Wildfly.
Table of Contents (15 chapters)
JBoss EAP6 High Availability
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

The design of mod_cluster


From the previous chapter, we know that JK uses a TCP port to communicate with the JBoss EAP6 server via AJP13 protocols. When compared with JK, mod_cluster uses the following three channels to serve its functions:

  • A connector channel supports the multiple protocols for the load balancer to proxy user requests to worker nodes. This part is almost synonymous with JK. The difference here is that besides the AJP13 protocol, mod_cluster also supports the HTTP/HTTPS protocols.

  • An advertising channel discovers worker nodes. This channel uses IP multicasting to transfer UDP datagrams. The load balancer will advertise itself in a multicast group, and the worker nodes will find it automatically by subscribing to this group.

  • A management channel is used to transfer status and management messages between the load balancer and the worker nodes. The protocol used by the management channel is an extension of the HTTP/1.1 protocol. The name of the protocol is MCMP.

When compared...