Java™ Application Development on Linux - Dator

458Chapter 20Open Source Web <strong>Application</strong> Serversappropriate symlinks to the rcX.d directories. 13 So, first we have to take aninit script and modify it to run JBoss.20.5.2 RedHat/Fedora chkconfigRedHat and its stepchild, Fedora, use a program called chkconfig to automatethe setup and integration of init scripts.The chkconfig program has four basic functions. Two involve adding andremoving services from management. That’s our main interest here, but we’llget to that in a moment. The other two involve querying and setting the runlevelsin which services run. That is the more common use, so we’ll look atthose first.[root@host238 root]# chkconfig --list ntpdntpd 0:off 1:off 2:off 3:on 4:off 5:on 6:offTIPchkconfig --list without specifying a service name will list all the servicesmanaged by chkconfig, including those that are provided by xinetd, which wewill not cover here.As you can see, ntpd runs at runlevels 3 and 5, and does not run at anyothers. The --list argument lets you query the runlevels.[root@host238 root]# chkconfig --levels 2345 ntpd on[root@host238 root]# chkconfig --list ntpdntpd 0:off 1:off 2:on 3:on 4:on 5:on 6:offThe --levels argument lets you specify a list of runlevels that will applyto the named service. The last argument may be on or off to specify whichsetting to apply to those runlevels. The current value (on or off) for a specified13. Just a quick reminder that not all Linux distributions name their directories or scripts inprecisely the same way, but they all use something similar. By examining the /etc/inittabfile and the contents of the /etc directory, you should be able to figure out the details of anygiven distribution. Over time, more and more distributions have come to exactly match thenaming scheme described here. RedHat, Fedora, and Debian, for example, all follow thisnaming scheme.