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TENTAKEL(1) DragonFly General Commands Manual TENTAKEL(1)
NAME
tentakel - distributed command execution
SYNOPSIS
tentakel [ -lhv ] [ -c file ] [ -g group ] [ command ]
DESCRIPTION
tentakel is a program for executing the same command on many hosts in
parallel using various remote methods.
It can make use of several sets of hosts that are defined in a
configuration file as groups.
The command is executed in parallel on all hosts in this group. By
default, every result is printed to stdout. The output format can be
defined for each group.
If no command is specified tentakel goes into interactive mode which
can be used for repeated commands.
The requirements on the remote hosts depend on the selected remote
method. The ssh method, for example, needs a running sshd on the remote
side. tentakel itself only needs to be installed on the controlling
host.
OPTIONS
-c file
Use file as the configuration file if specified, otherwise try
$HOME/.tentakel/tentakel.conf and finally /etc/tentakel.conf.
-g groupname
Select the group groupname The group must be defined in the
configuration file. If not specified tentakel implicitely
assumes the "default" group.
-l Display a list of possible group choices.
-h Display a brief help message.
-v Display version information.
command
The command that is to be executed on all hosts in the current
group. If command is omitted, tentakel starts in interactive
mode.
CONFIGURATION FILE
Everything appearing after a # character will be ignored to the next
newline. Leading whitespace will be ignored. Host and List objects
become members of the last named group declaration. Forward
declarations are allowed.
In the first section you may set global variables like:
set var="value"
value must be enclosed in double quotes even if it does not contain
spaces. To write the double quote characters itself in the value, you
have to write two successive double quote characters, e. g.
var="foo(""bar"")".
var must be one of the following:
ssh_path
The path where the ssh(1) binary is located.
rsh_path
The path where the rsh(1) binary is located.
method You can choose between "ssh" and "rsh" (ssh is the default). A
user may define additional methods by creating plugins, as
explained later.
user The user that is used to login to the remote host. If no user is
specified, the effective uid of the tentakel process is used.
format The format controls how the output of the remote command is
formatted. Most of the characters in format are output verbatim
while some character sequences are treated special:
\\ prints a literal \ character.
\n prints a newline character.
\t prints a tab character.
%c Denotes a formatting expression that is expanded
dynamically. Formatting expressions consist of a %
followed by a single character c and are expanded
depending on the value of c while c can be one of:
% a literal % character.
d expanded to the name of the destination (ip or
hostname).
o expanded to the output of the remote command.
s expanded to the exit status of the remote command.
t expanded to the time (in seconds) that was needed
to execute the remote command. This includes the
time for network overhead etc.
The default format is "### %d(stat: %s, dur(s): %t):\n%o\n".
maxparallel
Run at most maxparallel commands in parallel. This is useful to
avoid, for example, a command overloading a download server. "0"
means no limit (default). Setting it to "1" is more or less
senseless.
Group Definition
Definitions of groups make up the second section of the configuration
file. A new group is defined by a group statement of the form:
group name ( [ param1 [, param2 ... ] ] ) members
name must consist only of alphanumeric characters.
Inside the parentheses you can specify variables that follow the same
rules as the variables in the first section of the configuration file.
Those parameters override the global parameters for this specific
group. Parameters of sub-groups override those set in the enclosing
group. An exception from this rule is the maxparallel parameter, whose
value is always taken from the outermost group.
Group Members
A group definition ends with a whitespace-separated list of its
members. Each item takes the form of:
[ + | @ ] name
name must consist of alphanumeric characters but is additionally
allowed to contain dots. Each name is prepended by a type designator
which specifies the members type. Possible types are:
*name Host inclusion. name is included and can be an ip
address or a hostname.
@name Group inclusion. All members of group name are included.
Forward declarations are allowed.
Configuration File Example
set ssh_path="/usr/bin/ssh"
group myGroup (method="ssh", user="stark") +localhost @others
group others () +hostA +hostB +hostC
For more examples please see the example configuration file.
PLUGINS
The set of remote methods tentakel can use to execute commands can be
extended by means of plugins. A plugin is a single Python module and
must appear in the $HOME/.tentakel/plugins/ directory. Inside a plugin
an arbitrary number of subclasses of the RemoteCommand class may be
defined. Each class corresponds to one remote method.
By registering a plugin the set of possible choices for the method
parameter can be extended.
For further information please refer to the PLUGINS document which
should be contained in your tentakel installation.
INTERACTIVE MODE
The interactive mode has several advantages:
- it's easier if more than one command needs to be executed
- you can leave out some quoting for the command
- the current configuration can be changed interactively
The following commands are available in interactive sessions:
help command
Display a brief help message on command.
listgroups
Display a list of available groups.
use groupname
Set the current group to groupname.
hosts Display a list of affected hosts.
exec command
Execute command on all affected hosts.
conf Change the current configuration interactively. The default
editor command is /usr/bin/vi but can be overridden by setting
either of the VISUAL or EDITOR environment variables. Using the
conf command does only affect the configuration of the running
interactive tentakel process. It does not change any
configuration file.
quit Exit tentakel. The same can be done by pressing ctrl-d.
If the readline(3) library is installed on the system you can use the
tab key for automatic completion of partially entered command names.
EXAMPLES
$ tentakel -g myGroup uptime
This command executes the uptime(1) command on all hosts defined in
group myGroup. The whole output (even stderr) of each host is printed
according to the format string.
FILES
/etc/tentakel.conf
Site-wide configuration file.
$HOME/.tentakel/tentakel.conf
User-specific configuration file.
$HOME/.tentakel/plugins/
User-defined remote method plugins
The user-specific configuration file takes precedence over the site-
wide one.
BUGS
tentakel uses threads. This restricts the usage to platforms that have
a working threads implementation supported by Python.
Currently, ssh(1) and rsh(1) are the only supported remote methods.
REPORTING BUGS
Please visit http://tentakel.biskalar.de/. There you will find up-to-
date information about how to report bugs.
AUTHOR
Written by Sebastian Stark and Marlon Berlin.
SEE ALSO
ssh(1), rsh(1), http://tentakel.biskalar.de/
2003 December 28 TENTAKEL(1)