NAME
fai-class - define classes using files and scripts.
SYNOPSIS
fai-class [OPTION] DIRECTORY CLASSFILE
DESCRIPTION
fai-class executes scripts in DIRECTORY to define classes. All classes
are written to CLASSFILE, each class on a separate line. Use absolute
paths for both arguments. All scripts or executables matching
"[0-9][0-9]*" 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 ".source" 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 classes. After that, the
classes from the file $LOGDIR/additional-classes are added. Then, all
classes in the file with the hostname are added. Then 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 containg 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 a list of all classes is defined in a shell script using the
following command:
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-installation-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 (execpt 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://www.informatik.uni-koeln.de/fai.
AUTHOR
Written by Thomas Lange <lange@informatik.uni-koeln.de>