Overview of the cfengine setup

cfengine is an administation infrastructure used by the DESY computer center (see http://www.cfengine.org).

The two entry points in the cfengine configuration tree are:
$TFEAT (/afs/.ifh.de/common/installation/test/feature) and
$TARCH (/afs/.ifh.de/common/installation/test/archive).
$TFEAT is the branch containing the cfengine scripts, each of them
being in a directory having the corresponding feature name. The
name of the script itself is cf.feature_name. So, the full path of
the apemaster feature script is $TFEAT/apemaster/cf.apemaster .
$TARCH is the branch containing the "archive" of the cfengine
features, i.e. the master copy of the files relevant to each
feature. As an example, the master copy of the apemaster3 exports
file can be found in $TARCH/exports/apemaster3/etc/exports .
Warning! Not all the apemasters have a private copy of a configuration
file: if the same version is shared by some of them, there is a link
at a well defined point in the tree. To see what is shared, look at
the base of the feature archive, in our case $TARCH/exports:
fangorn:installation/test/feature 13> ls -l $TARCH/exports
total 38
drwxr-xr-x 3 danpop sysprog 2048 Nov 4 17:55 apemaster/
lrwxr-xr-x 1 danpop sysprog 9 Nov 4 17:56 apemaster0 -> apemaster/
lrwxr-xr-x 1 danpop sysprog 9 Nov 4 17:56 apemaster1 -> apemaster/
lrwxr-xr-x 1 danpop sysprog 9 Nov 4 17:56 apemaster2 -> apemaster/
drwxr-xr-x 3 danpop sysprog 2048 Nov 7 17:27 apemaster3/
lrwxr-xr-x 1 danpop sysprog 9 Nov 4 17:56 apemaster4 -> apemaster/
<snip>
So, be very careful when you want to make a change that should affect
only one apemaster.
For an understanding of the cfengine scripts, some basic knowledge about
cfengine is needed. The documentation relevant to the version that is
actually used at Zeuthen can be found at:
http://www.iu.hio.no/cfengine/docs/cfengine-1.6.3.Tutorial.html
http://www.iu.hio.no/cfengine/docs/cfengine-1.6.3.Reference.html
For a more comprehensive description of the Zeuthen setup, read the file
/afs/ifh.de/project/sue+cfengine/Notizen_zu_sue+cfengine .

Executing a cfengine feature

If immediate execution of a cfengine feature is needed, this can be done
like this:
The options -n and -v have the usual meaning (dry run and, respectively,
verbose mode). So, just to test a change to the apemaster feature, it is
recommended to use:
and carefully examine the command's output. If everything looks OK,
repeat the command without -n and check that the changes have been
performed as expected.

Syncronising cfengine and amsync

The apemaster cfengine feature creates a number of subtrees that are further
maintained by the amsync command. Because of this, if the amsync is ever
changed to use a different source for the apeshare, apeboot, zroot, kroot and
SGE features, these changes should be reflected in the apemaster cfengine
script.

Intranet-related changes to /etc/hosts

These changes have to made to $TARCH/hosts/AddOn/apemaster/etc/hosts.
Be sure that you have an AFS token before attempting to edit this file.
After the changes are made, the command
should be executed on each apemaster node, to update the local /etc/hosts file.
Then,
will update the filesystem exported to the unit PCs on all the apemaster nodes.