NAME

atnodes - Run command on clusters

SYNOPSIS

    # 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

USAGE

    atnodes [OPTIONS] COMMAND... -- HOST_PATTERN... [OPTIONS]
    atnodes [OPTIONS] COMMAND HOST_PATTERN... [OPTIONS]

OPTIONS

    -c <num>      Set SSH concurrency limit. (default: 20)
    -h            Print this help.
    -l            List the hosts and do nothing else.
    -L            Use the line-mode output format, i.e., prefixing
                  every output line with the machine name.
    -p <port>     Port for the remote SSH service.
    -ssh <path>   Specify an alternate ssh program.
                  (This overrides the SSH_BATCH_SSH_CMD environment.)
    -t <timeout>  Specify timeout for net traffic.
    -u <user>     User account for SSH login.
    -v            Be verbose.
    -w            Prompt for password (used for login and sudo).

PREREQUISITES

atnodes (as well as the other scripts bundled by SSH::Batch) requires the OpenSSH client executable (usually spelled "ssh") with multiplexing support (at least OpenSSH 4.1). To check your ssh version, use the command:

    $ ssh -v

On my machine, it echos

    OpenSSH_4.7p1 Debian-8ubuntu1.2, OpenSSL 0.9.8g 19 Oct 2007
    usage: ssh [-1246AaCfgKkMNnqsTtVvXxY] [-b bind_address] [-c cipher_spec]
               [-D [bind_address:]port] [-e escape_char] [-F configfile]
               [-i identity_file] [-L [bind_address:]port:host:hostport]
               [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port] [-R [bind_address:]port:host:hostport] [-S ctl_path]
               [-w local_tun[:remote_tun]] [user@]hostname [command]

There's no spesial requirement on the server side ssh service. Even a non-OpenSSH server-side deamon should work as well.

TUNING

By default, atnodes relies on Net::OpenSSH to locate the OpenSSH client executable "ssh". But you can define the SSH_BATCH_SSH_CMD environment to specify the command explicitly. You can use the -ssh option to override it further.

Note that to specify your own "ssh" is also a way to pass more options to the underlying OpenSSH client executable when using atnodes:

    $ cat > ~/bin/myssh
    #!/bin/sh
    # to enable X11 forwarding:
    exec ssh -X "$@"

    $ chmod +x ~/bin/myssh

    $ export SSH_BATCH_SSH_CMD=~/bin/myssh
    $ atnodes 'ls -lh' '{my_cluster_name}'

It's important to use "exec" in your own ssh wrapper script, or you may see atnodes hangs.

SEE ALSO

fornodes, tonodes, key2nodes, SSH::Batch, 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.