NAME

    clad - A simple parallel ssh client.

VERSION

    version 0.24

SYNOPSIS

        clad [log options] [-n] [-a] [-l login] <cluster> <command>

DESCRIPTION

    clad provides the ability to run the same command on several hosts at
    once. The output is displayed unbuffered as the various hosts run the
    command. The list of hosts is determined by reading a configuration
    file which associates names of clusters with lists of hosts. The
    configuration file may also contain command aliases and environment
    settings.

    The command(s) will be executed under '/bin/sh -e' regardless of the
    login shell for the remote user.

FEATURES

      * Cluster-specific and global environment settings

      * Event-driven unbuffered output (using Mojo::Reactor)

      * Host chaining support

      * Perlish configuration for dynamic cluster settings

      * Filtering of banners

      * Command aliases

      * Command macros

OPTIONS

    -n

      Dry run, just show the command that would be executed and each host.

    -a

      Don't colorize the host names in the output.

    -l

      Specify a login name for all ssh connections (proxies, too).

EXAMPLES

     clad -n mailhosts uname -a
     clad webservers df -kh
     clad --trace root webservers ping -i 1 localhost

CONFIGURATION

    The configuration file is a Clustericious::Config file (YAML or JSON
    Mojo::Template's ) and has three sections :

    env : environment settings for all commands run on all hosts.

    clusters : specifies the clusters. A cluster is a label and a list of
    hosts. Each host can be either a hostname or an array of hostnames. If
    it is an array of hostnames it will be treated as a sequence of hosts
    through which to proxy, e.g.

        ssh host1 ssh host2 ssh host3...

    If the first proxy host is the same for all the hosts in a cluster,
    then it can be given separately (see the example below).

    aliases : command aliases. These may be either a single command or a
    list of commands. Lists of commands will all be run in the same ssh
    session. Environment variables in the env section will be merged with
    the global environment settings.

    macros : command macros. These are a sequence of commands or aliases.
    They will be executed in sequence, starting a new connection with each
    one. Each command/alias may also optionally have a login associated
    with it.

    banners : banners which should be suppressed when displaying stderr.

SAMPLE CONFIGURATION

    A sample configuration file ~/etc/Clad.conf :

        ---
        env :
            PATH : /usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/bin
            PERL5LIB : /home/joe/perl5
        clusters :
            mailers :
                - mail1
                - mail2
                - mail3
            webservers :
                env  :
                    USER : bob
                hosts :
                     - web1
                     - web2
            testweb :
                proxy : test.example.com
                hosts :
                    - testweb1
                    - testweb2
        aliases :
            check_ports : lsof -i -n
            startweb : nginx start
            stopweb : nginx start
            restartweb :
                - apachectl stop
                - apachectl start
            config_pull :
                - cd /usr/local/etc
                - git pull
            build :
                - cd project
                - perl Build.PL
                - ./Build
                - ./Build test
                - ./Build install
        macros :
             release :
                - login : joe
                  command : build
                - login : dev
                  command : restartweb
         banners :
                - text : |
    
    
                    **********************************************
                    This is a welcome banner that you see whenever
                    you ssh to our server!
                    **********************************************
                    \n
                    \n

    Another example, using some Mojo::Template features :

        ---
        env :
            PATH : /usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/bin
            PERL5LIB : /home/joe/perl5
        clusters :
            mailers    : [ <%= join ',', map "mail".$_, 0..10 %> ],
            webservers : [ <%= `/usr/local/bin/list_my_web_servers` %> ]

NOTES

    Manipulating .ssh/config can also be used for proxying. For instance :

        Host webdev1
        ProxyCommand ssh firewall.example.com nc %h %p
    
        Host webdev2
        ProxyCommand ssh firewall.example.com nc %h %p

SEE ALSO

      * Clustericious::Admin

      * Clustericious::Config

      * Log::Log4perl::CommandLine

      * SSH::Batch

      * Net::OpenSSH::Parallel

      * Net::SSH::Mechanize

      * helm

AUTHOR

    original author: Brian Duggan

    current maintainer: Graham Ollis <plicease@cpan.org>

COPYRIGHT AND LICENSE

    This software is copyright (c) 2012 by NASA GSFC.

    This is free software; you can redistribute it and/or modify it under
    the same terms as the Perl 5 programming language system itself.