jammy (1) fai-class.1.gz

NAME

       fai-class - define classes using files and scripts.

SYNOPSIS

       fai-class [OPTION] DIRECTORY CLASSFILE

DESCRIPTION

       This command is only called internally by FAI and not directly by the user.

       fai-class  executes  scripts  in  DIRECTORY to define classes. All classes are written to CLASSFILE, each
       class will be placed on a  separate  line.  Use  absolute  paths  for  both  arguments.  All  scripts  or
       executables matching "^[0-9][0-9]*" (they start with two digits) are executed in alphabetical order. They
       can define classes by writing the names of the classes to stdout. Classes can be separated by  spaces  or
       written one on a line. All lines that start with a "#" are comment lines and are ignored.

       Shell  scripts  that end in ".sh" are sourced and can define classes by setting the variable $newclasses.
       This is useful for scripts where you can't control stdout. Variables that are defined  in  these  scripts
       are available to other scripts in DIRECTORY, but they are not exported to the shell that calls fai-class.
       Those scripts can define variables by writing definitions to the file $LOGDIR/additional.var, which  will
       be sourced in the following task.

       All  scripts can define additional classes by writing the classes to the file $LOGDIR/additional-classes.
       These classes are defined after all scripts are executed. This temporary file will be removed after use.

       The order of the classes is important because it defines the priority of the classes from  low  to  high.
       First, the class DEFAULT is defined, then all scripts are executed to define the classes. After that, the
       classes from the file $LOGDIR/additional-classes are added. Subsequently, all classes in  the  file  with
       the  hostname  are added. Finally classes defined by the variable ADDCLASSES are used. This variable must
       be a comma separated list of classes. You can define this variable on the kernel command line.

       Finally, the class with the hostname and LAST are defined.

       It's important that each line in a file containing a class name ends with a newline. If  the  newline  is
       missing on the last line of a file, this class can't be added.

       The exit code of every script is written to the file status.log in LOGDIR.

OPTIONS

       -d     Create debugging output.

       -h     Show help, version and summary of options.

       -T     Test  if  classes  in  CLASSFILE are defined multiple times. This should never happen. The test is
              executed after the classes are defined.

       -t tmpdir
              The file additional-classes is read from the directory tmpdir. Default value is /tmp/fai/.

       -v     Create verbose output.

EXAMPLES

       In FAI, fai-class is used in the following way:

          # fai-class /fai/class /tmp/fai/FAI_CLASSES

       Then the list of all classes is assigned to the variable classes.

           classes=`cat /tmp/fai/FAI_CLASSES`

EXAMPLES FOR SCRIPTS

       This is the script 01alias:

       #! /bin/sh

       catnc() { # cat but no comment lines
           grep -v "^#" $1
       }
       # echo architecture in upper case
       dpkg --print-architecture | tr /a-z/ /A-Z/
       uname -s | tr /a-z/ /A-Z/

       # all hosts named ant?? use the classes in file anthill
       case $HOSTNAME in
           ant??) catnc anthill ;;
       esac

       # a Beowulf cluster; all nodes except the master node
       # use classes from file class/atoms
       case $HOSTNAME in
           atom00) echo BEOWULF_MASTER ;;
           atom??) catnc atoms ;;
       esac

       # if host belongs to class C subnet 123.45.6.0 use class NET_6
       case $IPADDR in
           123.45.6.*) echo NET_6 ;;
       esac

       Another EXAMPLE:

       The script 24nis:

       #! /bin/sh

       # add NIS and the NIS domain name if YPDOMAIN is defined

       if [ -n "$YPDOMAIN" ];then
          echo "NIS $YPDOMAIN" | tr /.a-z-/ /_A-Z_/
       else
          echo NONIS
       fi

       You can define classes on the kernel command line by appening this to the kernel:

          ADDCLASSES=CLASS1,CLASSX,CLASS3

NOTES

       All class names should be written in uppercase letters (except the class of the hostname). Do not  use  a
       dash,  use  an  underscore.  Only  executable  scripts in DIRECTORY are used. CLASSFILE is removed before
       writing to it. Scripts should not directly  write  to  CLASSFILE.  LOGDIR  should  not  be  writable  for
       everybody.

SEE ALSO

       This program is part of FAI (Fully Automatic Installation). The FAI homepage is http://fai-project.org.

AUTHOR

       Written by Thomas Lange <lange@informatik.uni-koeln.de>