Home Switchboard Unix Administration Red Hat TCP/IP Networks Neoliberalism Toxic Managers
May the source be with you, but remember the KISS principle ;-)
Skepticism and critical thinking is not panacea, but can help to understand the world better

cexec - A utility that executes a given command on each node of a cluster

News  C3 Tools Recommended Links Parallel command execution c3.conf   C3 Environment variables
cexec cpush cget crm      
rdist rsync Parallel Tips History Humor Etc


cexec  is a utility that executes a given string on each node of a cluster.  syntax somewhat imitates ssh syntax (cluster:nodes)

This command is intended to be a general purpose utility for executing command on mutil servers. It has no real connection to HPC clusters, as such.

Cexec exists in two version

TIP: In case command contains double quote the whole command should be put in single quotes -- probably bug in cexec

cexec 'useradd -u 1003 -g 1003 -c "Medea application" -d /Apps/MD medea'




There are several basic ways to call cexec:

1. To simply execute a command on the default cluster:

cexec mkdir temp

this creates a directory named temp in your home directory

2. To execute a command on a subset of nodes on the default cluster

cexec :2-6 ls -l

this executes ls with the -l option on nodes of the first listed (default) cluster

3. To execute commands on a list of clusters

cexec cluster1: cluster2: ls -l

this executes ls with the -l option on all the nodes in both clusters

4. Quote position is important  if can you use pipes or other special symbols

cexec "ps -aux | grep root"

will execute ps on each node, grep for root there, sort the output, and display it on the screen

cexec ps -aux | grep root

will execute ps on each node, sort the output, grep out all the lines with root, and only display those lines to the screen. This removes all the formatting, to use C3 in this method the --pipe option should be used

Configuration files


This file is the cluster configuration file that contains the names of the nodes to which commands will be sent. The cluster configuration file of nodes may also be specified from the command line. The format of both files is identical.
see the c3.conf(5) man page for the format

Top Visited
Past week
Past month


Old News ;-)

Manpage of C3-SCALE

These examples will assume that the staging node includes itself in the responsibilities list. In the case where it is not included it would require an extra command so that the execution will take place on both the staging nodes and it's list of responsibilities. The most important option common throughout the C3 commands is the --all option. This option tells C3 to execute the given command on each and every cluster and node in the configuration file. It is recommended that the most commonly used or perhaps all of the C3 command be aliased to "command --all" for convenience. The following command will push /etc/passwd to every node in the scalable cluster:

cpush --all /etc/passwd

The other option is to explicitly list each sub-cluster on the command line. However, for large clusters this would be quite cumbersome if not impossible to do without human error. At this point using ranges on a scalable cluster is not as clean as using them on a non-scalable cluster. Because "node48" could be in any of the sub-clusters, or "node35-64" may cross several sub-cluster boundaries. These must be explicitly searched on and explicitly stated on the command line. For example searching in the first scalable configuration file:

cname --all node48 node35 node64

will return node 48 in part6 position 7, node35 in part5 position 1, node64 in part8 position 8. To execute on node48 use:

cexec part6:7 hostname

to execute on 35-64 use:

cexec part5:1-7 part6: part7: part8: hostname

Recommended Links

Google matched content

Softpanorama Recommended

Top articles


Top articles






Groupthink : Two Party System as Polyarchy : Corruption of Regulators : Bureaucracies : Understanding Micromanagers and Control Freaks : Toxic Managers :   Harvard Mafia : Diplomatic Communication : Surviving a Bad Performance Review : Insufficient Retirement Funds as Immanent Problem of Neoliberal Regime : PseudoScience : Who Rules America : Neoliberalism  : The Iron Law of Oligarchy : Libertarian Philosophy


War and Peace : Skeptical Finance : John Kenneth Galbraith :Talleyrand : Oscar Wilde : Otto Von Bismarck : Keynes : George Carlin : Skeptics : Propaganda  : SE quotes : Language Design and Programming Quotes : Random IT-related quotesSomerset Maugham : Marcus Aurelius : Kurt Vonnegut : Eric Hoffer : Winston Churchill : Napoleon Bonaparte : Ambrose BierceBernard Shaw : Mark Twain Quotes


Vol 25, No.12 (December, 2013) Rational Fools vs. Efficient Crooks The efficient markets hypothesis : Political Skeptic Bulletin, 2013 : Unemployment Bulletin, 2010 :  Vol 23, No.10 (October, 2011) An observation about corporate security departments : Slightly Skeptical Euromaydan Chronicles, June 2014 : Greenspan legacy bulletin, 2008 : Vol 25, No.10 (October, 2013) Cryptolocker Trojan (Win32/Crilock.A) : Vol 25, No.08 (August, 2013) Cloud providers as intelligence collection hubs : Financial Humor Bulletin, 2010 : Inequality Bulletin, 2009 : Financial Humor Bulletin, 2008 : Copyleft Problems Bulletin, 2004 : Financial Humor Bulletin, 2011 : Energy Bulletin, 2010 : Malware Protection Bulletin, 2010 : Vol 26, No.1 (January, 2013) Object-Oriented Cult : Political Skeptic Bulletin, 2011 : Vol 23, No.11 (November, 2011) Softpanorama classification of sysadmin horror stories : Vol 25, No.05 (May, 2013) Corporate bullshit as a communication method  : Vol 25, No.06 (June, 2013) A Note on the Relationship of Brooks Law and Conway Law


Fifty glorious years (1950-2000): the triumph of the US computer engineering : Donald Knuth : TAoCP and its Influence of Computer Science : Richard Stallman : Linus Torvalds  : Larry Wall  : John K. Ousterhout : CTSS : Multix OS Unix History : Unix shell history : VI editor : History of pipes concept : Solaris : MS DOSProgramming Languages History : PL/1 : Simula 67 : C : History of GCC developmentScripting Languages : Perl history   : OS History : Mail : DNS : SSH : CPU Instruction Sets : SPARC systems 1987-2006 : Norton Commander : Norton Utilities : Norton Ghost : Frontpage history : Malware Defense History : GNU Screen : OSS early history

Classic books:

The Peter Principle : Parkinson Law : 1984 : The Mythical Man-MonthHow to Solve It by George Polya : The Art of Computer Programming : The Elements of Programming Style : The Unix Haterís Handbook : The Jargon file : The True Believer : Programming Pearls : The Good Soldier Svejk : The Power Elite

Most popular humor pages:

Manifest of the Softpanorama IT Slacker Society : Ten Commandments of the IT Slackers Society : Computer Humor Collection : BSD Logo Story : The Cuckoo's Egg : IT Slang : C++ Humor : ARE YOU A BBS ADDICT? : The Perl Purity Test : Object oriented programmers of all nations : Financial Humor : Financial Humor Bulletin, 2008 : Financial Humor Bulletin, 2010 : The Most Comprehensive Collection of Editor-related Humor : Programming Language Humor : Goldman Sachs related humor : Greenspan humor : C Humor : Scripting Humor : Real Programmers Humor : Web Humor : GPL-related Humor : OFM Humor : Politically Incorrect Humor : IDS Humor : "Linux Sucks" Humor : Russian Musical Humor : Best Russian Programmer Humor : Microsoft plans to buy Catholic Church : Richard Stallman Related Humor : Admin Humor : Perl-related Humor : Linus Torvalds Related humor : PseudoScience Related Humor : Networking Humor : Shell Humor : Financial Humor Bulletin, 2011 : Financial Humor Bulletin, 2012 : Financial Humor Bulletin, 2013 : Java Humor : Software Engineering Humor : Sun Solaris Related Humor : Education Humor : IBM Humor : Assembler-related Humor : VIM Humor : Computer Viruses Humor : Bright tomorrow is rescheduled to a day after tomorrow : Classic Computer Humor

The Last but not Least Technology is dominated by two types of people: those who understand what they do not manage and those who manage what they do not understand ~Archibald Putt. Ph.D

Copyright © 1996-2020 by Softpanorama Society. was initially created as a service to the (now defunct) UN Sustainable Development Networking Programme (SDNP) without any remuneration. This document is an industrial compilation designed and created exclusively for educational use and is distributed under the Softpanorama Content License. Original materials copyright belong to respective owners. Quotes are made for educational purposes only in compliance with the fair use doctrine.

FAIR USE NOTICE This site contains copyrighted material the use of which has not always been specifically authorized by the copyright owner. We are making such material available to advance understanding of computer science, IT technology, economic, scientific, and social issues. We believe this constitutes a 'fair use' of any such copyrighted material as provided by section 107 of the US Copyright Law according to which such material can be distributed without profit exclusively for research and educational purposes.

This is a Spartan WHYFF (We Help You For Free) site written by people for whom English is not a native language. Grammar and spelling errors should be expected. The site contain some broken links as it develops like a living tree...

You can use PayPal to to buy a cup of coffee for authors of this site


The statements, views and opinions presented on this web page are those of the author (or referenced source) and are not endorsed by, nor do they necessarily reflect, the opinions of the Softpanorama society. We do not warrant the correctness of the information provided or its fitness for any purpose. The site uses AdSense so you need to be aware of Google privacy policy. You you do not want to be tracked by Google please disable Javascript for this site. This site is perfectly usable without Javascript.

Last modified: March 12, 2019