Java™ Application Development on Linux - Dator

20.5 Things That Make It Go451TIPAt this point we suggest using one more Linux filesystem trick. The tarball unpacksinto a directory whose name includes the product version—in this case,jboss-3.2.3. In many cases, you will want to be able to have more than oneversion of JBoss installed on a box simultaneously, either because you need toport projects from one version to another, or perhaps because you need to developapplications that will run on different versions on different target servers.To make your life easier, create a symbolic link to a generically named directory,such as jboss, and have that symlink point to jboss-3.2.3. Then you canwrite your startup and shutdown scripts to use the jboss pathname. You canthen switch to another version by changing where the symlink points:$ cd /usr/local$ ln -s jboss-3.2.3 jbossThis process is discussed in detail in Section 6.2 in the context of switchingbetween Java SDK versions.20.5THINGS THAT MAKE IT GOIn order to explain how to integrate an Open Source application server intoyour system, we have to do a little Linux Sysadmin training. We need to showyou how server processes are generally managed on Linux systems.20.5.1 System V Init SystemVirtually all Linux distributions use some variant of the System V init systemto create and customize programs and services that run at the startup of thebox. Now, we don’t want to write a Linux system administration manual, butwe do need to tell you enough to decide how to make JBoss available whenneeded on your server.The core of the System V init system is the /etc/inittab file. Everythingelse devolves from this configuration file. In the days before network services,the primary startup tasks were to get getty programs running and then run asingle startup shell script. The /etc/inittab file handles these tasks beautifully.Since then, the world of UNIX and Linux has become a complex mixtureof client-server programs and protocols, so a complex set of conventions hasbeen developed to turn the primitive /etc/inittab into a much richer set of