man cssh (Commandes) - Cluster administration tool


cssh (crsh) - Cluster administration tool


cssh [options] [[user@]<server>|<tag>] [...] crsh [options] [[user@]<server>|<tag>] [...]


The command opens an administration console and an xterm to all specified hosts. Any text typed into the administration console is replicated to all windows. All windows may also be typed into directly.

This tool is intended for (but not limited to) cluster administration where the same configuration or commands must be run on each node within the cluster. Performing these commands all at once via this tool ensures all nodes are kept in sync.

Connections are opened via ssh so a correctly installed and configured ssh installation is required. If, however, the program is called by crsh then the rsh protocol is used (and the communcations channel is insecure).

Extra caution should be taken when editing system files such as /etc/inet/hosts as lines may not necessarily be in the same order. Assuming line 5 is the same across all servers and modifying that is dangerous. Better to search for the specific line to be changed and double-check before changes are committed.

Further Notes

The dotted line on any sub-menu is a tear-off, i.e. click on it and the sub-menu is turned into its own window.
Unchecking a hostname on the Hosts sub-menu will unplug the host from the cluster control window, so any text typed into the console is not sent to that host. Re-selecting it will plug it back in.
If the code is called as crsh instead of cssh (i.e. a symlink called crsh points to the cssh file or the file is renamed) rsh is used as the communcations protocol instead of ssh.
Starting the utility will be much faster with a configuration file (as this prevents searching for required files). Generate one containing all default entries with: CWcssh -u > $HOME/.csshrc
When using cssh on a large number of systems to connect back to a single system (e.g. you issue a command to the cluster to scp a file from a given location) and when these connections require authentication (i.e. you are going to authenticate with a password), the sshd daemon at that location may refuse connects after the number specified by MaxStartups in sshd_config is exceeded. (If this value is not set, it defaults to 10.) This is expected behavior; sshd uses this mechanism to prevent DoS attacks from unauthenticated sources. Please tune sshd_config and reload the SSH daemon, or consider using the ~/.ssh/authorized_keys mechanism for authentication if you encounter this problem.
If client windows fail to open, try running cssh -d <single host name>. This will output a command to run which will test the method used by cssh to open client windows. If you copy-and-paste this command into a window and it fails, this is the issue. It is most likely due to the -xrm option which enables AllowSendEvents in the terminal. Some terminal do not require this option, other terminals have another method for enabling it. See your terminal documention for further information.


Some of these options may also be defined within the configuration file. Default options are shown as appropriate.

Show basic help text, and exit
Show full help test (the man page), and exit
Show version information and exit
Enable basic debugging mode (can be combined with -D)
Enable extended debugging mode (can be combined with -d)
Enable|Disable automatically quiting after the last client window has closed (overriding the config file)
Output configuration in the format used by the $HOME/.csshrc file
Enable|Disable window tiling (overriding the config file)
-c <file>
Use supplied file as additional cluster file (see also FILES) Specify the default username to use for connections (if different from the currently logged in user). NOTE: will be overridden by <user>@<host> Specify the initial part of the title used in the console and client windows Specify arguments to be passed to ssh or rsh when making the connection. Specify arguments to be passed to terminals being used
Ignore errors from resolving host names (i.e. because the name is an alias within an ssh config file or similar) (see also ignore_host_errors in FILES)


The following arguments are support:

[usr@]<hostname> ...
Open an xterm to the given hostname and connect to the administration console.
<tag> ...
Open a series of xterms defined by <tag> within either /etc/clusters or $HOME/.csshrc (see FILES).


The following key shortcuts are available within the console window, and all of them may be changed via the configuration files.

Quit the program and close all connections and windows
Open the Add Host dialogue box
Paste in the correct client name to all clients, i.e. CWscp /etc/hosts server:files/<Alt-n>.hosts would replace the <Alt-n> with the client's name in all the client windows
Retile all the client windows


This file contains a list of tags to server names mappings. When any name is used on the command line it is checked to see if it is a tag in /etc/clusters (or the .csshrc file, or any addition cluster file specified by -c). If it is a tag, then the tag is replaced with the list of servers from the file. The file is formated as follows: <tag> [user@]<server> [user@]<server> [...] i.e. # List of servers in live live admin1@server1 admin2@server2 server3 server4 All standard comments and blank lines are ignored. Tags may be nested, but be aware of recursive tags.
/etc/csshrc & $HOME/.csshrc
This file contains configuration overrides - the defaults are as marked. Default options are overwritten first by the global file, and then by the user file.
always_tile = yes
Setting to anything other than CWyes does not perform window tiling (see also -G).
auto_quit = yes
Automatically quit after the last client window closes. Set to anything other than yes to disable. Can be overridden by CW-Q on the command line.
comms = ssh
Sets the default communication method (initially taken from the name of program, but can be overridden here).
console_position = <null>
Set the initial position of the console - if empty then let the window manager decide. Format is '+<x>+<y>', i.e. '+0+0' is top left hand corner of the screen, '+0-70' is bottom left hand side of screen (more or less).
rsh_args = <blank>
Sets any arguments to be used with the communication method (defaults to ssh arguments). NOTE: the given defaults are based on OpenSSH, not commercial ssh software. If set to yes, ignore host names that cannot be resolved (i.e. because they are aliased in an ssh config file) - see also -i
key_addhost = Control-plus
Default key sequence to open AddHost menu. See below notes on shortcuts.
key_clientname = Alt-n
Default key sequence to send cssh client names to client. See below notes on shortcuts.
key_quit = Control-q
Default key sequence to quit the program (will terminate all open windows). See below notes on shortcuts.
key_retilehosts = Alt-r
Default key sequence to retile host windows. See below notes on shortcuts.
screen_reserve_top = 25
screen_reserve_bottom = 30
screen_reserve_left = 0
screen_reserve_right = 0
Number of pixels from the screen side to reserve when calculating screen geometry for tiling. Setting this to something like 50 will help keep cssh from positioning windows over your window manager's menu bar if it draws one at that side of the screen.
ssh = /path/to/ssh
rsh = /path/to/rsh
Depending on the value of comms, set the path of the communication binary.
terminal = /path/to/terminal
Path to the x-windows terminal used for the client.
terminal_args = <blank>
Arguments to use when opening terminal windows. Otherwise takes defaults from $HOME/.Xdefaults or $<$HOME/.Xresources> file.
terminal_font = 6x13
Font to use in the terminal windows
terminal_reserve_top = 0
terminal_reserve_bottom = 0
terminal_reserve_left = 0
terminal_reserve_right = 0
Number of pixels from the terminal side to reserve when calculating screen geometry for tiling. Setting these will help keep cssh from positioning windows over your scroll and title bars
terminal_size = 80x24
Initial size of terminals to use (note: the number of lines (24) will be decreased when resizing terminals for tiling, not the number of characters (80))
terminal_title_opt = -T
Option used with CWterminal to set the title of the window
terminal_allow_send_events = -xrm 'XTerm.VT100.allowSendEvents:true'
Option required by the terminal to allow XSendEvents to be received
title = cssh
Title of windows to use for both the console and terminals.
use_hotkeys = yes
Setting to anything other than CWyes will disable all hotkeys. Sets the default user for running commands on clients.
window_tiling = yes
Perform window tiling (set to CWno to disable)
window_tiling_direction = right
Direction to tile windows, where right means starting top left and moving right and then down, and anything else means starting bottom right and moving left and then up NOTE: The key shortcut modifiers must be in the form Control, Alt, or Shift, i.e. with the first letter capitalised and the rest lower case. Keys may also be disabled individually by setting to the work null.


Duncan Ferguson


clusterssh is distributed under the GNU public license. See the file LICENSE for details.

A web site for comments, requests, bug reports and bug fixes/patches is available at <>


None are known at this time


If you require support, please run the following commands and post it on the web site in the support/problems forum: CWperl -V CWperl -MTk -e 'print $Tk::VERSION,$/' CWperl -MX11::Protocol -e 'print $X11::Protocol::VERSION,$/'
Use the debug switches (-d, -D, or -dD) will turn on debugging output. However, please only use this option with one host at a time, i.e. cssh -d <host> due to the amount of output produced (in both main and child windows).


<>, ssh, Tk::overview, X11::Protocol, perl