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| Whatsup |
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Description:
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Whatsup is cluster node up/down detection utility. 

The whatsup package includes:

* libnodeupdown
  - A C library to determine up or down nodes in a cluster.  See
    libnodeupdown(3)

* Libnodeupdown.pm
  - A Perl module developed with Perl Extensions that takes advantage
    of the already available C library.  Perl extensions is limited
    and provides an unorthodox Perl API.  It is therefore recommended
    most users use Nodeupdown.pm.  See Libnodeupdown(3).

* Nodeupdown.pm
  - A Perl module that interfaces with Libnodeupdown.pm, hiding away
    the ugliness of Libnodeupdown.pm.  See Nodeupdown(3).

* whatsup
  - A command that outputs the up and down nodes in a cluster. See
    whatsup(1).

Backend Tools:
--------------

The nodeupdown library works in conjunction with one of several
possible backend tools.

The currently available backend tools are:

Pingd: A simple daemon that regularly pings cluster nodes.

Ganglia: See http://ganglia.sourceforge.net

Cerebro: See http://cerebro.sourceforge.net

The Pingd daemon is distributed along with whatsup as a subpackage.

OpenIB: Query's the opensm (SA) for node up information.  This requires the
hostname to be reported as the HCA's "node description".  Currently Mellanox
HCA's and OFED 1.1 or greater provide for this information.  More information
can be found at http://openib.org

Clusterlist Definitions:
------------------------

The nodeupdown library can also work in conjunction with several
cluster databases.

Genders - Uses a genders database and the genders library to determine
all nodes in the cluster. (http://sourceforge.net/projects/genders)

Hostsfile - Uses a file that lists the hostname of every node in the
cluster on a separate line.

Whatsup Options:
----------------

A few additional options may be available for the tool Whatsup dependent
on your environment and the modules installed.  The following are the
currently supported options modules to Whatsup:

cerebro-monitor: Supports the -M or --monitor option.  Will monitor
and output all changes in state to cluster nodes through the cerebro
'updown' event.

Install:
--------

For whatsup to work, you must install and configuration one of the
backend tools for your system.  The appropriate backend module for the
libnodeupdown library must then be installed.  If more than one module
is installed, the first one discovered will be used.

A clusterlist module and clusterlist database does not need to be
installed for whatsup to work, however it would be beneficial to
define one.

Comments, patches, fixes, suggestions are always welcome.  Please read
DISCLAIMER and COPYING for copyright and license information.

Albert Chu
chu11@llnl.gov
Lawrence Livermore National Laboratory