cexec.1 (2012 03)

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cexec(1) cexec(1)

-h | --help | -?

Displays commands and use information from cexec

and quits.

-l | --user user

Runs remote commands as another user, subject to authorization. When using remsh, the user

issuing the command must be authorized in the remote user’s /.rhosts. When using ssh, the

local cexec user must have performed a key exchange with the speciﬁed remote ssh user.

-R | --rcmd {ssh | rsh}

Set remote command transport option to the transport, either

ssh or rsh.

-r | --retry={all | fail | success} reportfile

cexec retries commands on the nodes on which they were targeted to run in the reportﬁle

speciﬁed.

retry=fail re-runs the command only on the failed nodes,

retry=all re-runs

the commands on all nodes,

-retry=success

re-runs the command on nodes where it suc-

cessfully ran earlier.

Report ﬁles can be renamed. When renamed, they do not need the .rpt ﬁle extension, but they

must be in the $HOME/.cexec/reports directory.

-report_loc

Displays the location of the reports that

cexec

generates. When this option is used, it

displays the command and the reports it generated. All reports are located in the

$HOME/.cexec/reports directory. The user cannot change the location of the reports.

-t | --timeout seconds

Sets the connect timeout in seconds.

-u | --ctime seconds

Sets a limit on the amount of time a remote command is allowed to execute. Default is no

limit.

-V | --version

Shows the version of

cexec.

ENVIRONMENT VARIABLES

When not running on a Serviceguard cluster, if no other node selection option is used, the

CFANOUT_HOSTS environment variable may be set to a ﬁlename from which a list of target hosts is

read. The ﬁle should contain a list of hosts, one per line.

NETWORKING FEATURES

cexec is based on the pdsh(1) command. pdsh supports remsh or the rsh protocol as a command

transport. remsh and its related utilities like rlogin(1) have well documented security shortcomings.

For unprivileged users to use the remsh transport of pdsh and cexec, the /opt/dsau/bin/pdsh pro-

gram must be owned by root and the SUID bit must be set, just like the /usr/bin/remsh program. As

shipped, the

pdsh binary is owned by user bin and the SUID bit is not set. Thus an unprivileged user

cannot use the "-R rsh" option until the system administrator explicitly enables it. The system adminis-

trator should only enable pdsh usage of remsh in environments where users and hosts are trusted. The

default ssh transport offers signiﬁcantly better security. The csshsetup tool makes ssh as easy to

conﬁgure as the .rhosts ﬁle of remsh.

LIMITATIONS

cexec assumes a predeﬁned security setup when using remsh and ssh transports. Neither transport

can prompt for a password. For remsh, the user’s /.rhosts must be appropriately conﬁgured. For ssh,a

public key distribution must be performed to all targeted hosts. For the ssh case, the csshsetup tool is

provided to make the ssh setup as simple as possible. For example, csshsetup makes it easy to set up

any node to any node trust relationships in a Serviceguard cluster for groups of managed systems.

For the ssh transport, the connect timeout is not adjustable.

Hostlist parsing assumes numerical part of hostname is at the end only, for example, specifying

remote[0-5]host will not work.

You cannot use interactive commands (commands that prompt for input or expect a tty to be present).

The number of nodes on which

cexec can simultaneously execute remote jobs is limited by the maximum

number of threads that can be created concurrently and the availability of reserved ports in rsh rcmd

modules.

2 Hewlett-Packard Company − 2 − HP-UX 11i Version 3: March 2012