Provided by: clusterssh_4.05-2_all bug


       ccon - Cluster administration tool


       ccon [-K <seconds>] [-q] [-c '<filename>'] [-C '<filename>'] [--debug [[...] ||
       <INTEGER>]] [-d] [-e '<[user@]<host>[:port]>'] [-f '<font>'] [-h] [-L '[tag]'] [-H] [-M
       '<STRING>'] [-p <port>] [-Q] [-s] [-r '<filename>'] [-t '<STRING>'] [-g] [-T '<title>']
       [-u] [-?] [-A] [-v]


       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 using console which must be correctly installed and configured.

       Extra caution should be taken when editing files as lines may not necessarily be in the
       same order;  assuming line 5 is the same across all servers and modifying that is
       dangerous.  It's better to search for the specific line to be changed and double-check all
       terminals are as expected before changes are committed.

   Further Notes
       Please also see "KNOWN BUGS".

       ·   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 your window manager menu bars are obscured by terminal windows see the
           "screen_reserve_XXXXX" options in the $HOME/.clusterssh/config file (see "FILES").

       ·   If the terminals overlap too much see the "terminal_reserve_XXXXX" options in the
           $HOME/.clusterssh/config file (see "FILES").

       ·   When using ClusterSSH on a large number of systems to connect to a single system using
           an SSH utility (e.g. you issue a command to to copy a file using scp from the remote
           computers to a single host) and when these connections require authentication (i.e.
           you are going to authenticate with a password), the sshd daemon at that location may
           refuse connections after the number "MaxStartups" limit 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:

           "ccon -e {single host name}"

           This will test the mechanisms used to open windows to hosts.  This could be due to
           either the "-xrm" terminal option which enables "AllowSendEvents" (some terminals do
           not require this option, other terminals have another method for enabling it - see
           your terminal documentation) or the configuration of "console".


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

       --autoclose <seconds>, -K <seconds>
           Number of seconds to wait before closing finished terminal windows.

       --autoquit, -q
           Toggle automatically quiting after the last client window has closed (overriding the
           config file).

       --cluster-file '<filename>', -c '<filename>'
           Use supplied file as additional cluster file (see also "FILES").

       --config-file '<filename>', -C '<filename>'
           Use supplied file as additional configuration file (see also "FILES").

       --debug [[...] || <INTEGER>]
           Enable debugging.  Either a level can be provided or the option can be repeated
           multiple times.  Maximum level is 4.

       --dump-config, -d
           Dump the current configuration in the same format used by the $HOME/.clusterssh/config

       --evaluate '<[user@]<host>[:port]>', -e '<[user@]<host>[:port]>'
           Display and evaluate the terminal and connection arguments to display any potential
           errors.  The <hostname> is required to aid the evaluation.

       --font '<font>', -f '<font>'
           Specify the font to use in the terminal windows. Use standard X font notation such as

       --help, -h
           Show basic help text and exit

       --list '[tag]', -L '[tag]'
           List available cluster tags. Tag is optional.  If a tag is provided then hosts for
           that tag are listed.  NOTE: format of output changes when using "--quiet" or "-Q"

       --man, -H
           Show full help text (the man page) and exit

       --master '<STRING>', -M '<STRING>'
           The console client program polls master as the primary server, rather than the default
           set at compile time (typically ``console'').

       --port <port>, -p <port>
           Specify an alternate port for connections.

       --quiet, -Q
           Do not output extra text when using some options

       --show-history, -s
           Show history within console window.

       --tag-file '<filename>', -r '<filename>'
           Use supplied file as additional tag file (see also "FILES")

       --term-args '<STRING>', -t '<STRING>'
           Specify arguments to be passed to terminals being used.

       --tile, -g
           Toggle window tiling (overriding the config file).

       --title '<title>', -T '<title>'
           Specify the initial part of the title used in the console and client windows.

       --unique-servers, -u
           Toggle connecting to each host only once when a hostname has been specified multiple

       --usage, -?
           Show synopsis and exit

       --use-all-a-records, -A
           If a hostname resolves to multiple IP addresses, toggle whether or not to connect to
           all of them, or just the first one (see also config file entry).

       --version, -v
           Show version information and exit


       The following arguments are supported:

       [user@]<hostname>[:port] ...
           Open an xterm to the given hostname and connect to the administration console.  The
           optional port number can be used if the server is not listening on the standard port.

       <tag> ...
           Open a series of xterms defined by <tag> in one of the supplementary configuration
           files (see "FILES").

           Note: specifying a username on a cluster tag will override any usernames defined in
           the cluster.


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

           Open the 'Add Host(s) or Cluster(s)' dialogue box.  Multiple host or cluster names can
           be entered, separated by spaces.

           Paste in the hostname part of the specific connection string to each client, minus any
           username or port, e.g.

           "scp /etc/hosts server:files/<Alt-n>.hosts"

           would replace the <Alt-n> with the client's name in each window.

           Paste in the hostname of the server cssh is ebing run on

           Quit the program and close all connections and windows.

           Retile all the client windows.

           Paste in the username for the connection


       Open up a session to 3 servers
           $ ccon server1 server2 server3

       Open up a session to a cluster of servers identified by the tag 'farm1' and give the
       controlling window a specific title, where the tag is defined in one of the default
       configuration files
           $ ccon -T 'Web Farm Cluster 1' farm1

       Connect to different servers using different login names.  NOTE: this can also be achieved
       by setting up appropriate options in the configuration files.  Do not close the console
       when the last terminal exits.
           $ ccon user1@server1 admin@server2

       Open up a cluster defined in a non-default configuration file
           $ ccon -c $HOME/cssh.extra_clusters db_cluster

       Override the configured/default port to use 2022 instead
           $ ccon -p 2022 server1 server2


       /etc/clusters, $HOME/.clusterssh/clusters
           These files contain 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.  If it is a tag, then the tag is
           replaced with the list of servers.  The format is as follows:

           <tag> [user@]<server>[:port] [user@]<server>[:port] [...]


               # List of servers in live
               live admin1@server1 admin2@server2:2022 server3 server4

           All comments (marked by a #) and blank lines are ignored.  Tags may be nested, but be
           aware of using recursive tags as they are not checked for.

           Extra cluster files may also be specified either as an option on the command line (see
           "cluster-file") or in the user's $HOME/.clusterssh/config file (see
           "extra_cluster_file" configuration option).

           NOTE: the last tag read overwrites any pre-existing tag of that name.

           NOTE: there is a special cluster tag called "default" - any tags or hosts included
           within this tag will be automatically opened if nothing is specified on the command

       /etc/tags, $HOME/.clusterssh/tags
           Very similar to clusters files but the definition is reversed.  The format is:

           <host> <tag> [...]

           This allows one host to be specified as a member of a number of tags.  This format can
           be clearer than using clusters files.

           Extra tag files may be specified either as an option (see "tag-file") or within the
           user's $HOME/.clusterssh/config file (see "extra_tag_file" configuration option).

           NOTE: All tags are added together

       /etc/csshrc & $HOME/.clusterssh/config
           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.

           NOTE: values for entries do not need to be quoted unless it is required for passing
           arguments, e.g.

           "terminal_allow_send_events="-xrm '*.VT100.allowSendEvents:true'""

           should be written as

           "terminal_allow_send_events=-xrm '*.VT100.allowSendEvents:true'"

           auto_close = 5
               Close terminal window after this many seconds.  If set to 0 will instead wait on
               input from the user in each window before closing. See also --autoclose and

           auto_quit = 1
               Automatically quit after the last client window closes.  Set to 0 to disable.  See
               also --autoquit

           comms = console
               Sets the default communication method (initially taken from the name of the
               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).

           external_cluster_command = <null>
               Define the full path to an external command that can be used to resolve tags to
               host names.  This command can be written in any language.  The script must accept
               a list of tags to resolve and output a list of hosts (space separated on a single
               line).  Any tags that cannot be resolved should be returned unchanged.

               A non-0 exit code will be counted as an error, a warning will be printed and
               output ignored.

               If the external command is given a "-L" option it should output a list of tags
               (space separated on a single line) it can resolve

           extra_cluster_file = <null>
               Define an extra cluster file in the format of /etc/clusters.  Multiple files can
               be specified, separated by commas.  Both ~ and $HOME are acceptable as a reference
               to the user's home directory, e.g.

               "extra_cluster_file = ~/clusters, $HOME/clus"

           key_addhost = Control-Shift-plus
               Default key sequence to open AddHost menu.  See "KEY SHORTCUTS" for more

           key_clientname = Alt-n
               Default key sequence to send cssh client names to client.  See "KEY SHORTCUTS" for
               more information.

           key_localname = Alt-l
               Default key sequence to send hostname of local server to client.  See "KEY
               SHORTCUTS" for more information.

           key_paste = Control-v
               Default key sequence to paste text into the console window.  See "KEY SHORTCUTS"
               for more information.

           key_quit = Control-q
               Default key sequence to quit the program (will terminate all open windows).  See
               "KEY SHORTCUTS" for more information.

           key_retilehosts = Alt-r
               Default key sequence to retile host windows.  See "KEY SHORTCUTS" for more

           key_username = Alt-u
               Default key sequence to send username to client.  See "KEY SHORTCUTS" for more

           macro_servername = %s
           macro_hostname = %h
           macro_username = %u
           macro_newline = %n
           macro_version = %v
               Change the replacement macro used when either using a 'Send' menu item, or when
               pasting text into the main console.

           macros_enabled = yes
               Enable or disable macro replacement.  Note: this affects all the "macro_*"
               variables above.

           max_addhost_menu_cluster_items = 6
               Maximum number of entries in the 'Add Host' menu cluster list before scrollbars
               are used

           max_host_menu_items = 30
               Maximum number of hosts to put into the host menu before starting a new column

           menu_host_autotearoff = 0
           menu_send_autotearoff = 0
               When set to non-0 will automatically tear-off the host or send menu at program

           mouse_paste = Button-2 (middle mouse button)
               Default key sequence to paste text into the console window using the mouse.  See
               "KEY SHORTCUTS" for more information.

           rsh = /path/to/rsh
           ssh = /path/to/ssh
           telnet = /path/to/telnet
               Set the path to the specific binary to use for the communication method, else uses
               the first match found in $PATH

           rsh_args = <blank>
           ssh_args = "-x -o ConnectTimeout=10"
           telnet_args = <blank>
               Sets any arguments to be used with the communication method (defaults to ssh

               NOTE: The given defaults are based on OpenSSH, not commercial ssh software.

               NOTE: Any "generic" change to the method (e.g., specifying the ssh port to use)
               should be done in the medium's own config file (see "ssh_config" and

           screen_reserve_top = 0
           screen_reserve_bottom = 60
           screen_reserve_left = 0
           screen_reserve_right = 0
               Number of pixels from the screen's 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.

           terminal = /path/to/xterm
               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_chdir = 0
               When non-0, set the working directory for each terminal as per

           terminal_chdir_path = $HOME/.clusterssh/work/%s
               Path to use as working directory for each terminal when 'terminal_chdir' is
               enabled.  The path provided is passed through the macro parser (see the section
               above on 'macros_enabled'.

           terminal_font = 6x13
               Font to use in the terminal windows.  Use standard X font notation.

           terminal_reserve_top = 5
           terminal_reserve_bottom = 0
           terminal_reserve_left = 5
           terminal_reserve_right = 0
               Number of pixels from the terminal's side to reserve when calculating screen
               geometry for tiling.  Setting these will help keep cssh from positioning windows
               over your scroll and title bars or otherwise overlapping the windows too much.

           terminal_colorize = 1
               If set to 1 (the default), then "-bg" and "-fg" arguments will be added to the
               terminal invocation command-line.  The terminal will be colored in a pseudo-random
               way based on the host name; while the color of a terminal is not easily predicted,
               it will always be the same color for a given host name.  After a while, you will
               recognize hosts by their characteristic terminal color.

           terminal_bg_style = dark
               If set to "dark", the terminal background will be set to black and the foreground
               to the pseudo-random color.  If set to "light", then the foreground will be black
               and the background the pseudo-random color.  If terminal_colorize is "zero", then
               this option has no effect.

           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 "terminal" to set the title of the window

           terminal_allow_send_events = -xrm '*.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.

           unmap_on_redraw = no
               Tell Tk to use the UnmapWindow request before redrawing terminal windows.  This
               defaults to "no" as it causes some problems with the FVWM window manager.  If you
               are experiencing problems with redraws, you can set it to "yes" to allow the
               window to be unmapped before it is repositioned.

           use_all_a_records = 0
               If a hostname resolves to multiple IP addresses, set to 1 to connect to all of
               them, not just the first one found.  See also "--use-all-a-records"}

           use_hotkeys = 1
               Setting to 0 will disable all hotkeys.

           use_natural_sort = 0
               Windows will normally sort in alphabetical order, i.e.: host1, host11, host2.
               Setting to this 1 will change the sort order, i.e.: host1, host2, host11. NOTE:
               You must have the perl module Sort::Naturally installed.

           user = $LOGNAME
               Sets the default user for running commands on clients.

           window_tiling = 1
               Perform window tiling (set to 0 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", e.g.
           with the first letter capitalised and the rest lower case.  Keys may also be disabled
           individually by setting to the word "null".

           This (optional) file contains items to populate the send menu.  The default entry
           could be written as:

               <menu title="Use Macros">
               <menu title="Remote Hostname">
               <menu title="Local Hostname">
               <menu title="Username">
               <menu title="Test Text">
                   <command>echo "ClusterSSH Version: %v%n</command>

           Submenus can also be specified as follows:

               <menu title="Default Entries">
                 <menu title="Hostname">


           There is currently no strict format checking of this file.
           The format of the file may change in the future
           If the file exists, the default entry (Hostname) is not added

           The following replacement macros are available (note: these can be changed in the
           configuration file):

           %s  Hostname part of the specific connection string to each client, minus any username
               or port

           %u  Username part of the connection string to each client

           %h  Hostname of server where cssh is being run from

           %n  "RETURN" code

           NOTE: requires XML::Simple to be installed


       If you have any ideas about how to fix the below bugs, please get in touch and/or provide
       a patch.

       ·   Swapping virtual desktops can cause a redraw of all the terminal windows.  This is due
           to a lack of distinction within Tk between switching desktops and
           minimising/maximising windows.  Until Tk can tell the difference between the two
           events, there is no fix (apart from rewriting everything directly in X).


       ·   If you have issues running ccon, first try:

           "ccon -e [user@]<hostname>[:port]"

           This performs two tests to confirm cssh is able to work properly with the settings
           provided within the $HOME/.clusterssh/config file (or internal defaults).

           1.  Test the terminal window works with the options provided

           2.  Test console works to a host with the configured arguments

           Configuration options to watch for in ssh are

           SSH doesn't understand "-o ConnectTimeout=10" - remove the option from the
           $HOME/.clusterssh/config file
           OpenSSH-3.8 using untrusted ssh tunnels - use "-Y" instead of "-X" or use
           "ForwardX11Trusted yes" in $HOME/.ssh/ssh_config (if you change the default ssh
           options from "-x" to "-X")
       ·   If you require support, please run the following commands and post it on the web site
           in the support/problems forum:

           "perl -V"

           "perl -MTk -e 'print $Tk::VERSION,$/'"

           "perl -MX11::Protocol -e 'print $X11::Protocol::VERSION,$/'"

           "cat /etc/csshrc $HOME/.clusterssh/config"

       ·   Using the debug option (--debug) will turn on debugging output.  Repeat the option to
           increase the amount of debug.  However, if possible please only use this option with
           one host at a time, e.g. "cssh --debug <host>" due to the amount of output produced
           (in both main and child windows).


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


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


       Duncan Ferguson, "<duncan_j_ferguson at>"


       Copyright 1999-2015 Duncan Ferguson.

       This program is free software; you can redistribute it and/or modify it under the terms of
       either: the GNU General Public License as published by the Free Software Foundation; or
       the Artistic License.

       See for more information.