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wulfstat

NAME

wulfstat - A simple project template

SYNOPSIS

wulfstat [-h] [-v] [-t display_type] [-d delay] [-c count]
           [-f /path/to/wulfhosts] [-l]

WULFSTAT OPTIONS

 -h shows help (command synopsis).
 -v makes execution verbose for debugging or the bored.
 -t display_type selects display type from list below
 -d delay (in seconds) selects update loop delay
 -c count causes it to output only count times and exit (for debugging)
 -f /path/to/wulfhosts to use a particular wulfhosts file
 -l show localhost only (use no wulfhosts file from any location)

DESCRIPTION

wulfstat is a simple yet powerful tty (ncurses) based cluster monitoring tool. It requires xmlsysd (running on each system to be monitored) to efficiently provide it with system and proc-derived information that is processed and provided to the user in one of several user-selectable display formats. With it a user can monitor things across en entire beowulf, cluster, or workstation LAN systems descriptors such as load average, memory consumption, swap, page, and interrupt activity and network loads or can even retrieve and display such mundane information is CPU make and base clock, system time, uptime or other potentially useful but slowly varying system descriptors. The information presented is updated regularly after a user-selectable delay. The tool allows displays to be selected or changed while the application is running, and more hosts or nodes can be displayed than will easily fit on a single e.g. xterm by paging through them with key-based commands.

WULFHOST

To run wulfhost as anything but a monitor of the local host one REQUIRES a wulfhost file. wulfstat run with no viable wulfhost file defaults to a localhost connection. A localhost connection can also be forced (overriding the search for a wulfhost file) with the -l command line argument.

The wulfhost file tells wulfstat where to to connect to xmlsysd's. It consists of any mix of the following xml discriptors:

<?xml version="1.0"?>

<wulfstat>

  <root/>
  <user>rgb</user>
  <task>On_spin3d</task>

  <host>
    <name>ganesh</name>
  </host>

  <host>
     <ip>192.168.1.132</ip>
    <port>7887</port>
  <host>

  <host>
    <name>lucifer</name>
    <ip>192.168.1.131</ip>
    <port>7887</port>
  </host>

  <hostrange>
    <hostfmt>g%02d</hostfmt>
    <imin>1</imin>
    <imax>15</imax>
    <port>7887</port>
  </hostrange>

  <iprange>
    <ipmin>152.3.182.193</ipmin>
    <ipmax>152.3.182.200</ipmax>
    <port>7887</port>
  </iprange>

</wulfstat>

From this example, one sees that the <host></host> tag defines a host to connect to. Within this tag, the host can be specified by the <name></name> tag (which can contain any name resolvable by gethostbyname()) or the <ip></ip> tag, most commonly used for hosts in a cluster that haven't been named. In addition, for each host one can specify a <port></port> if one for any reason is running the xmlsysd on a different port than its installation default.

This information can easily be overspecified. In most cases, for example, it is better to just use the default port (7887) and let local hostname ip address lookup take care of determining the interface IP number. Note that xml doesn't care how the tags are laid out as long as they are nested correctly, and that there can be more than one <host>, <hostrange>, or <iprange> tagset in a wulfhosts to specify the simultaneous monitoring of any mix of hosts, clusters, lans.

Note also that xml DOES preserve whitespace, so

  <host><name>b0 </name></host>

is NOT the same is

  <host><name>b0</name></host>

and would likely not work correctly. If you do enter port, name, and ip explicitly and incorrectly or inconsistently, be prepared for odd behavior.

The <hostrange> is hopefully self explanatory. It can be used to rapidly define an entire cluster on the basis of a systematic ordering of hostname. The contents of the <hostfmt> tag should be a SIMPLE printf-format string for a presumed integer that will be iterated from <imin> to <imax> in steps of one. In this way a single xml tag can define an entire cluster e.g. g01-g15.

The <iprange> is similar, except that it uses ip number directly in <ipmin> and <ipmax>. Use caution -- in almost all cases the first three tuples in the ip number should be the SAME in <ipmin> and <ipmax>. This option is provided in case the hosts don't have a well-defined and published hostname and are accessible only by e.g. dhcp-assigned ip number in any event.

All forms of defining a host or list of hosts permit an optional <port> to be assigned to override xmlsysd's installation default of 7887.

wulfstat will connect to these hosts as fast as it can in a parallel thread, and then will periodically attempt to REconnect to any hosts that might be down or that might go down while wulfstat is running. wulfstat itself is thus moderately robust against cluster node state changes, although this is an area still being debugged (1/9/03).

wulfstat looks for a useable wulfhosts file in many places (in order):

  NO wulfhosts file (localhost only) via the -l flag;
  where it is directed by the -f /path/to/wulfhosts command line option;
  in ./wulfhosts (in the current working directory);
  in $HOME/.wulfhosts (in the home directory, note the ".");
  in the file pointed to by environment variable WULFHOSTS;
  in /etc/wulfhosts;

and if it can find none of them it tries to come up on localhost.

Note that any hosts that do not resolve are displayed but marked unknown. Any hosts that resolve but that cannot accept a connection (which could mean that no daemon is installed or running, the daemon has more connections than the number permitted in e.g. /etc/xinetd.d/xmlsysd, or that the host is down) are marked down.

DISPLAY TYPES

The following display types are supported by wulfstat:

  0 - load and status only (default), a very useful display for cluster 
      users
  1 - stat -- information and rates primary derived from /proc/stat
  2 - memory only (similar to running "free" on each host)
  3 - network rates
  4 - time displays system clocks, uptime, cpu type and clock
  5 - "user" interface for monitoring distributed tasks by username or 
      taskname (experimental).

Each of these interfaces can also be reached interactively within wulfstat by typing the first letter as shown on the menu.

INTERACTIVE COMMANDS

wulfstat also permits things like delay, display type and quit to be selected with single keystrokes when the mouse focus is in the window. Single-key commands it recognizes include:

  q(uit)

  +/- increments or decrements the delay clock, zero is the minimum permitted value and basically spins wulfstat as fast as it can spin, which is useful for creating a modest "load" on cpu or network so you can see wulfstat work.

  PgUp displays the next page of hosts
  PgDn displays the last page of hosts 
  UpArrow scrolls the display up
  DnArrow scrolls the display down

in a circular queue. Using these keys a user can rapidly cycle through quite large clusters.

  l(oad) selects the cpu load display  (likely the most useful)
  m(emory) selects the memory display
  n(etwork) selects the network load display
  t(ime) selects the time (and cpu info) display
  u(ser) selects the user task interface (experimental).

Finally, if there is enough room (it is recommended that wulfstat be used with at least 35x80 xterms or larger) a debug window will rarely display interesting messages. Starting wulfstat with a -v option will increase the noisiness in this window, but isn't recommended unless you are debugging the wulfstat source for some reason.

DEBUGGING

To help debug wulfstat (or problems you might have with wulfhosts), note the table of verbose/debugging values that is printed as part of its Usage (-h flag). This yields anything from a simple trace of a particular subsystem such as connect_hosts() to everything the program does. To limit the output, one can also use the -c count flag to only display a single cycle. It is a good idea to pipe stderr into a logfile separately so that the display output is unaltered. The logfile can be examined later or mailed back to me for analysis.

An example of this might be:

  wulfstat -l -c 1 -v 10 2>connect_hosts.log

to trace what wulfstat does connecting to localhost.

SEE ALSO

libwulf(3), wulflogger(1)

PUBLICATION RULES

wulfstat can be modified and used at will by any user, provided that:

  a) The original copyright notices are maintained and that the source, including all modifications, is made publically available at the time of any derived publication. This is open source software according to the precepts and spirit of the Gnu Public License. See the accompanying file COPYING, which also must accompany any redistribution.

  b) The author of the code (Robert G. Brown) is appropriately acknowledged and referenced in any derived use or publication.

  c) Full responsibility for the accuracy, suitability, and effectiveness of the program rests with the users and/or modifiers. As is clearly stated in the accompanying copyright.h:

THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

ACKNOWLEDGEMENTS

None to speak of now, but a good place to comply with b) above later, if you hack this code. Well, I should probably acknowledge the essential help of Icon (Konstantin Raibetsev) and Seth Vidal, the entire beowulf list, and various books on xml, network programming (e.g. Stevens) and a cast of thousands. So let's assume that I just did;-)

GPL 2b; see the file COPYING that accompanies the source of this program. This is the "standard Gnu General Public License version 2 or any later version", with the one minor (humorous) "Beverage" modification listed below. Note that this modification is probably not legally defensible and can be followed really pretty much according to the honor rule.

As to my personal preferences in beverages, red wine is great, beer is delightful, and Coca Cola or coffee or tea or even milk acceptable to those who for religious or personal reasons wish to avoid stressing my liver.

The Beverage Modification to the GPL:

Any satisfied user of this software shall, upon meeting the primary author(s) of this software for the first time under the appropriate circumstances, offer to buy him or her or them a beverage. This beverage may or may not be alcoholic, depending on the personal ethical and moral views of the offerer. The beverage cost need not exceed one U.S. dollar (although it certainly may at the whim of the offerer:-) and may be accepted or declined with no further obligation on the part of the offerer. It is not necessary to repeat the offer after the first meeting, but it can't hurt...