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GNU cfengine

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6.2 `cfrc' resource file

If, for some reason you are not satisfied with the defaults which cfengine uses, then you can change them by making an entry in the resource file. The default values are defined in the source code file classes.c in the distribution. The format of the resource file is:

 
hardclass.variable: value

For example, you might want to forget about where your HPUX system mounts its mail directory and mount it under /usr/spool/mail. In this case you would add the line:

 
hpux.maildir: /usr/spool/mail

To redefine the filesystem table for GNU/linux, you would write:
 
linux.fstab: /etc/linuxfstab

The full list of re-definable resources is:

 
   mountcomm       # command used to mount filesystems
   unmountcomm     # command used to unmount filesystems
   ethernet        # name of the ethernet device
   mountopts       # options to above mount command
   fstab           # the name of the filesystemtable
   maildir         # the location of the mail directory
   netstat         # the full path to netstat and options
   pscomm          # the path to the system's ps command
   psopts          # the options used by ps (default aux/ef)

You should never need to redefine resources unless you decide to do something non-standard. Interested readers are referred to the values in classes.c.

Cfengine is easily extensible so as to support a variety of architectures. You can even add your own. To do so you need, first of all, to define a new class for the operating system concerned. The file classes.c has been separated off from the remainder of the source code so that you can easily see which data structures need to be extended.

To make life as straightforward as possible, three unused classes have been defined. They are called (unremarkably) unused1, unused2 and unused3. If you add any further classes, it will be necessary to increase the constant clssattr defined in cf.defs.h by one for every new addition. You do not need to change clssattr if you simple replace one of the unused classes by a real class.

To see fully the impact of what you need to do, you should make a search for the strings unused? in all of the source files. Certain special cases need to be handled for each operating system. For example, the form of the filesystem table is quite radically different on some systems such as AIX. One thing you must do is to fill in the default values for the new operating system in the file classes.c.

If you fill in the details for a new operating system before it finds its way into a new release, you might consider sending the details to the bug list in the next paragraph.


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