NAME
    SSH::Batch - Cluster operations based on parallel SSH, set and interval
    arithmetic

SYNOPSIS
    The following scripts are provided:

    fornodes
        Expand patterns to machine host list.

            $ cat > ~/.fornodesrc
            ps=blah.ps.com bloo.ps.com boo[2-25,32,41-70].ps.com
            as=ws[1101-1105].as.com
            # use set operations to define new sets:
            foo={ps} + {ps} * {as} - {ps} / {as}
             bar = foo.com bar.org \
                bah.cn \
                baz.com
            ^D

            $ fornodes 'api[02-10].foo.bar.com' 'boo*.ps.com'
            $ fornodes 'tq[ab-ac].[1101-1105].foo.com'
            $ fornodes '{ps} + {as} - ws1104.as.com'  # set union and subtraction
            $ fornodes '{ps} * {as}'  # set intersect

    atnodes
        Run command on clusters. (atnodes calls fornodes internally.)

            # run a command on the specified servers:
            $ atnodes $'ps -fe|grep httpd' 'ws[1101-1105].as.com'

            # multiple-arg command requires "--":
            $ atnodes ls /opt/ -- '{ps} + {as}' 'localhost'

            # or use single arg command:
            $ atnodes 'ls /opt/' '{ps} + {as}' 'localhost' # ditto

            # specify a different user name and SSH server port:
            $ atnodes hostname '{ps}' -u agentz -p 12345

            # use -w to prompt for password if w/o SSH key (no echo back)
            $ atnodes hostname '{ps}' -u agentz -w

            # or prompt for password if sudo required...
            $ atnodes 'sudo apachectl restart' '{ps}' -w

            # or specify a timeout:
            $ atnodes 'ping foo.com' '{ps}' -t 3

    tonodes
        Upload local files/directories to remote clusters

            $ tonodes /tmp/*.inst -- '{as}:/tmp/'
            $ tonodes foo.txt 'ws1105*' :/tmp/bar.txt

            # use rsync instead of scp:
            $ tonodes foo.txt 'ws1105*' :/tmp/bar.txt -rsync

            $ tonodes -r /opt /bin/* -- 'ws[1101-1102].foo.com' 'bar.com' :/foo/bar/

    key2nodes
        Push the SSH public key (or generate one if not any) to the remote
        clusters.

            $ key2nodes 'ws[1101-1105].as.com'

DESCRIPTION
    This is a high-level abstraction over the powerful Net::OpenSSH module.
    A bunch of handy scripts are provided to simplify big cluster
    operations: fornodes, atnodes, tonodes, and key2nodes.

    Parallel SSH communication is used to ensure minimal latency.

TODO
    *   Add a "-c" option to the scripts to limit ssh concurrency level.

INSTALLATION
        perl Makefile.PL
        make
        make test
        sudo make install

    Win32 users should replace "make" with "nmake".

SOURCE CONTROL
    You can always get the latest SSH::Batch source from its public Git
    repository:

        http://github.com/agentzh/sshbatch/tree/master

    If you have a branch for me to pull, please let me know ;)

SEE ALSO
    fornodes, atnodes, tonodes, key2nodes, SSH::Batch::ForNodes,
    Net::OpenSSH.

COPYRIGHT AND LICENSE
    This module as well as its programs are licensed under the BSD License.

    Copyright (c) 2009, Yahoo! China EEEE Works, Alibaba Inc. All rights
    reserved.

    Copyright (C) 2009, Agent Zhang (agentzh). All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are
    met:

    *   Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.

    *   Redistributions in binary form must reproduce the above copyright
        notice, this list of conditions and the following disclaimer in the
        documentation and/or other materials provided with the distribution.

    *   Neither the name of the Yahoo! China EEEE Works, Alibaba Inc. nor
        the names of its contributors may be used to endorse or promote
        products derived from this software without specific prior written
        permission.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
    IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
    TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
    PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
    OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
    EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
    PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
    PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
    LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
    NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
    SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.