pdcp - Online in the Cloud

PROGRAM:

NAME

pdcp - copy files to groups of hosts in parallel
rpdcp - (reverse pdcp) copy files from a group of hosts in parallel

SYNOPSIS

pdcp [options]... src [src2...] dest
rpdcp [options]... src [src2...] dir

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).

REVERSE PDCP

rpdcp performs a reverse parallel copy. Rather than copying files to remote hosts, files
are retrieved from remote hosts and stored locally. All directories or files retrieved
will be stored with their remote hostname appended to the filename. The destination file
must be a directory when this option is used.

In other respects, rpdcp is exactly like pdcp, and further statements regarding pdcp in
this manual also apply to rpdcp.

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 TARGETS,...
Target and or filter 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. Arguments in the TARGETS list may include normal host
names, a range of hosts in hostlist format (See HOSTLIST EXPRESSIONS), or a single
`-' character to read the list of hosts on stdin.

If a host or hostlist is preceded by a `-' character, this causes those hosts to be
explicitly excluded. If the argument is preceded by a single `^' character, it is
taken to be the path to file containing a list of hosts, one per line. If the item
begins with a `/' character, it is taken as a regular expression on which to
filter the list of hosts (a regex argument may also be optionally trailed by
another '/', e.g. /node.*/). A regex or file name argument may also be preceeded
by a minus `-' to exclude instead of include thoses hosts.

A list of hosts may also be preceded by "user@" to specify a remote username other
than the default, or "rcmd_type:" to specify an alternate rcmd connection type for
these hosts. When used together, the rcmd type must be specified first, e.g.
"ssh:user1@host0" would use ssh to connect to host0 as user "user1."

-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 the HOSTLIST EXPRESSIONS section below). Arguments to -x may
also be preceeded by the filename (`^') and regex ('/') characters as described
above, in which case the resulting hosts are excluded as if they had been given to
-w and preceeded with the minus `-' character.

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.

-e PATH
Explicitly specify path to remote pdcp binary instead of using the locally executed
path. Can also be set via the environment variable PDSH_REMOTE_PDCP_PATH.

-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.

-M name,...
When multiple misc modules provide the same options to pdsh, the first module
initialized "wins" and subsequent modules are not loaded. The -M option allows a
list of modules to be specified that will be force-initialized before all others,
in-effect ensuring that they load without conflict (unless they conflict with
eachother). This option may also be set via the PDSH_MISC_MODULES environment
variable.

-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 only adjustable with ssh when the underlying ssh
implementation supports it, and pdsh has been built to use the correct option.

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