pdcp(1): copy files to groups of hosts in ...

NAME

pdcp - copy files to groups of hosts in parallel

DESCRIPTION

pdcp is a variant of the rcp(1) command. Unlike rcp(1), which copies files to a single remote host, pdcp can copy files to multiple remote hosts in parallel. However, pdcp does not recognize files in the format ``rname@rhost:path,'' therefore all source files must be on the local host machine. Destination nodes must be listed on the pdcp command line using a suitable target nodelist option (See the OPTIONS section below). Each destination node listed must have pdcp installed for the copy to succeed.

When pdcp receives SIGINT (ctrl-C), it lists the status of current threads. A second SIGINT within one second terminates the program. Pending threads may be canceled by issuing ctrl-Z within one second of ctrl-C. Pending threads are those that have not yet been initiated, or are still in the process of connecting to the remote host.

Like pdsh(1), the functionality of pdcp may be supplemented by dynamically loadable modules. In pdcp, the modules may provide a new connect protocol (replacing the standard rsh(1) protocol), filtering options (e.g. excluding hosts that are down), and/or host selection options (e.g. -a selects all nodes from a local config file). By default, pdcp requires at least one "rcmd" module to be loaded (to provide the channel for remote copy).

RCMD MODULES

The method by which pdcp connects to remote hosts may be selected at runtime using the -R option (See OPTIONS below). This functionality is ultimately implemented via dynamically loadable modules, and so the list of available options may be different from installation to installation. A list of currently available rcmd modules is printed when using any of the -h, -V, or -L options. The default rcmd module will also be displayed with the -h and -V options.

A list of rcmd modules currently distributed with pdcp follows.

rsh: Uses an internal, thread-safe implementation of BSD rcmd(3) to run commands using the standard rsh(1) protocol.
ssh: Uses a variant of popen(3) to run multiple copies of the ssh(1) command.
mrsh: This module uses the mrsh(1) protocol to execute jobs on remote hosts. The mrsh protocol uses a credential based authentication, forgoing the need to allocate reserved ports. In other aspects, it acts just like rsh.
krb4: The krb4 module allows users to execute remote commands after authenticating with kerberos. Of course, the remote rshd daemons must be kerberized.
xcpu: The xcpu module uses the xcpu service to execute remote commands.

OPTIONS

The list of available pdcp options is determined at runtime by supplementing the list of standard pdcp options with any options provided by loaded rcmd and misc modules. In some cases, options provided by modules may conflict with each other. In these cases, the modules are incompatible and the first module loaded wins.

Standard target nodelist options

-w host,host,...: Target the specified list of hosts. Do not use with any other node selection options (e.g. -a, -g if they are available). No spaces are allowed in the comma-separated list. A list consisting of a single `-' character causes the target hosts to be read from stdin, one per line. The host list may contain hostlist expressions of the form ``host[1-5,7]''. For more information about the hostlist format, see the HOSTLIST EXPRESSIONS section below.
-x host,host,...: Exclude the specified hosts. May be specified in conjunction with other target node list options such as -a and -g (when available). Hostlists may also be specified to the -x option (see HOSTLIST EXPRESSIONS secion below).

Standard pdcp options

-h: Output usage menu and quit. A list of available rcmd modules will be printed at the end of the usage message.
-q: List option values and the target nodelist and exit without action.
-b: Disable ctrl-C status feature so that a single ctrl-C kills parallel copy. (Batch Mode)
-r: Copy directories recursively.
-p: Preserve modification time and modes.
-l user: This option may be used to copy files as another user, subject to authorization. For BSD rcmd, this means the invoking user and system must be listed in the user's .rhosts file (even for root).
-t seconds: Set the connect timeout. Default is 10 seconds.
-f number: Set the maximum number of simultaneous remote copies to number. The default is 32.
-R name: Set rcmd module to name. This option may also be set via the PDSH_RCMD_TYPE environment variable. A list of available rcmd modules may be obtained via either the -h or -L options.
-L: List info on all loaded pdcp modules and quit.
-d: Include more complete thread status when SIGINT is received, and display connect and command time statistics on stderr when done.
-V: Output pdcp version information, along with list of currently loaded modules, and exit.

HOSTLIST EXPRESSIONS

As noted in sections above, pdcp accepts ranges of hostnames in the general form: prefix[n-m,l-k,...], where n < m and l < k, etc., as an alternative to explicit lists of hosts. This form should not be confused with regular expression character classes (also denoted by ``[]''). For example, foo[19] does not represent foo1 or foo9, but rather represents a degenerate range: foo19.

This range syntax is meant only as a convenience on clusters with a prefixNN naming convention and specification of ranges should not be considered necessary -- the list foo1,foo9 could be specified as such, or by the range foo[1,9].

Some examples of range usage follow:

Copy /etc/hosts to foo01,foo02,...,foo05
    pdcp -w foo[01-05] /etc/hosts /etc

Copy /etc/hosts to foo7,foo9,foo10
    pdcp -w foo[7,9-10] /etc/hosts /etc

Copy /etc/hosts to foo0,foo4,foo5
    pdcp -w foo[0-5] -x foo[1-3] /etc/hosts /etc

As a reminder to the reader, some shells will interpret brackets ('[' and ']') for pattern matching. Depending on your shell, it may be necessary to enclose ranged lists within quotes. For example, in tcsh, the first example above should be executed as:

pdcp -w "foo[01-05]" /etc/hosts /etc

ORIGIN

Pdsh/pdcp was originally a rewrite of IBM dsh(1) by Jim Garlick <garlick@llnl.gov> on LLNL's ASCI Blue-Pacific IBM SP system. It is now also used on Linux clusters at LLNL.

LIMITATIONS

When using ssh for remote execution, stderr of ssh to be folded in with that of the remote command. When invoked by pdcp, it is not possible for ssh to prompt for confirmation if a host key changes, prompt for passwords if RSA keys are not configured properly, etc.. Finally, the connect timeout is not adjustable when ssh is used.

Host range parsing assumes numerical part of hostname is at the end, e.g. specifying foo[0-5]bar will not work.