Linux Journal | April 2015

106 Pages·2015·14.75 MB·English

™
LUCI4HPC:
the Lightweight,
User-Friendly
Cluster
Management Tool
Since 1994: The Original Magazine of the Linux Community APRIL 2015 | ISSUE 252 | www.linuxjournal.com
-
HIGH PERFORMANCE
COMPUTING
JAILHOUSE
Real-Time
Security-Wise
Virtualization
PLUS
Explore the
Concepts of
STDIN, STDOUT
and STDERR
Write a Script
to Generate
Word Searches
WATCH:
HOW-TO: CREATE
ISSUE
OVERVIEW
Installing Libreboot Dynamic Content
▲
on an x60 with Django Templates
LJ252-April2015.indd 1 4/2/15 10:31 AM
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CONTENTS APRIL 2015
ISSUE 252
HIGH-PERFORMANCE COMPUTING
FEATURES
68 LUCI4HPC 78 Jailhouse
LUCI4HPC aims at providing an Explore a simple, compact, yet
easy and convenient tool to set real-world Linux hypervisor striving
up and maintain an in-house to cover use cases that others
high-performance computer cluster. don’t quite fit.
Melanie Grandits, Valentine Sinitsyn
Axel Sündermann
and Chris Oostenbrink
ON THE COVER
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Cover Image: © Can Stock Photo Inc. / alexaldo
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COLUMNS IN EVERY ISSUE
34 Reuven M. Lerner’s 8 Current_Issue.tar.gz
At the Forge
Letters
10
Django Templates
UPFRONT
16
42 Dave Taylor’s 32 Editors’ Choice
Work the Shell
New Products
64
Where’s That Pesky Hidden Word?
Advertisers Index
103
Kyle Rankin’s
48
Hack and /
Libreboot on an x60, Part II:
the Installation
Shawn Powers’
56
The Open-Source Classroom
Pipes and STDs
Doc Searls’ EOF
94
Consent That Goes Both Ways 24
68
LINUX JOURNAL (ISSN 1075-3583) is published monthly by Belltown Media, Inc., 2121 Sage Road, Ste. 395, Houston, TX 77056 USA. Subscription rate is $29.50/year. Subscriptions start with the next issue.
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Executive Editor Jill Franklin
[email protected]
Senior Editor Doc Searls
[email protected]
Associate Editor Shawn Powers
[email protected]
Art Director Garrick Antikajian
[email protected]
Products Editor James Gray
[email protected]
Editor Emeritus Don Marti
[email protected]
Technical Editor Michael Baxter
[email protected]
Senior Columnist Reuven Lerner
[email protected]
Security Editor Mick Bauer
[email protected]
Hack Editor Kyle Rankin
lj@greenfly.net
Virtual Editor Bill Childers
[email protected]
Contributing Editors
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Current_Issue.tar.gz
High
SHAWN POWERS
Performance:
a Relative Term
M y Pebble watch has several this issue should tickle your fancy.
orders of magnitude We start out with Django
more power than the templates, as Reuven M. Lerner
mainframe computers used by NASA builds on last month’s column about
to land astronauts on the moon the “atfproject” he started. Whether
and then get them back safely. In you want to develop with Django
fact, at the time, the six-megabyte or not, Reuven’s lessons always are
program IBM developed to monitor beneficial to the new programmer
the astronaut’s biometric and and the seasoned developer alike.
environmental data was the most Dave Taylor follows with a topic that
complex software ever written! is half scripting and half brain teaser.
Times certainly have changed, but How can you make a script to create
our desire to push computing to the words in a word search? Is a
its very limit surely hasn’t. This brute-force, every possible iteration
month is the High-Performance solution the best way? Dave starts
Computing issue of Linux Journal, the script this month and urges us
and whether you plan to land to send him ideas.
humans on the moon or analyze Kyle Rankin continues last issue’s
weather data over the Atlantic, article on Libreboot. We deal with
the operating systems (specifically
Linux!) all the time, but Kyle dives
deeper and explains how to replace
VIDEO:
(cid:86)
Shawn Powers runs the system BIOS with an open
through the latest issue.
alternative. My column isn’t nearly
8 / APRIL 2015 / WWW.LINUXJOURNAL.COM
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CURRENT_ISSUE.TAR.GZ
With a friendly Web interface and high
customization ability, LUCI4HPC might
be perfect for your needs.
as low-level, but it addresses an solutions very well. If you need
often confusing concept for Linux real-time solutions, but want the
users—namely, system I/O. If cost benefits of virtualization,
STDIN, STDOUT and STDERR sound Jailhouse might be perfect.
scary, fear not. I explore I/O in all Finally, Doc Searls tears open the
its glory and round things out with “Do Not Track” concept and explores
a clearer understanding of pipes its meaning, intent, current state
and redirects too. and future. If you, or your users, are
You will get a really clear look concerned about who gets access to
at LUCI4HPC this month, as what data, Doc’s column will be of
Melanie Grandits, Axel Sündermann particular interest this month.
and Christ Oostenbrink explain In fact, as a Linux user, this
the lightweight clustering system. entire issue is full of articles that
Although clustering often is needed most likely will pique your interest.
only in specialized circumstances, Whether you want to rewrite the
it doesn’t mean the process needs BIOS on your laptop or just want
to be difficult. With a friendly Web some free cash (be sure to read
interface and high customization my UpFront article on ChangeTip),
ability, LUCI4HPC might be perfect this issue aims to please. Add the
for your needs. product news, tech tips, kernel
(cid:54)(cid:65)(cid:76)(cid:69)(cid:78)(cid:84)(cid:73)(cid:78)(cid:69) (cid:51)(cid:73)(cid:78)(cid:73)(cid:84)(cid:83)(cid:89)(cid:78) (cid:68)(cid:69)(cid:83)(cid:67)(cid:82)(cid:73)(cid:66)(cid:69)(cid:83) updates and so on, and you have on
how to use Jailhouse this month. your screen a great way to spend
Although it might seem like “just April 1st—no fooling!(cid:81)
another virtualization platform”,
Jailhouse is designed with real-time Shawn Powers is the Associate Editor for Linux Journal.
virtualization in mind. For folks in He’s also the Gadget Guy for LinuxJournal.com, and he has
system automation, medical and an interesting collection of vintage Garfield coffee mugs.
telecommunications, real-time Linux Don’t let his silly hairdo fool you, he’s a pretty ordinary guy
is crucial. Sadly, most virtualization and can be reached via e-mail at [email protected].
systems don’t handle real-time Or, swing by the #linuxjournal IRC channel on Freenode.net.
WWW.LINUXJOURNAL.COM / APRIL 2015 / 9
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letters
an implementation in your next
great column.
—Hans
Dave Taylor replies: Thanks for
your kind note, Hans! As you have
no doubt figured out by now, I’m
more intrigued by algorithms and
implementations than I am by the
weird corner-case tricks and shortcuts
in the Bash shell. My logic is that
obfuscated code might be neat, but
it’s not elegant and therefore also
isn’t maintainable. I hate reading
Shuffling Cards—Dave Taylor someone else’s undocumented shell
I love your column, although I script that requires hours to figure
think you concentrate a bit too out. That’s just not good coding.
much on the application and too We’re not in the 1960s where every
little on interesting bash tricks. kilobyte counts, after all!
Now I know these are hard to find,
or perhaps what is trivial for one I’ll check out the algorithm, but
is new to the other. Perhaps the truth be told, I’m heading down
same also applies with the shuffling a different path starting with the
cards algorithm from your February column I owe LJ today—one that’s
2015 column. There is this “well” tied to a project I promised my
known algorithm from Fisher-Yates. 11-year-old a while back, a program
See Wikipedia for the details. It is that can create word searches.
embarrassingly straightforward
once you understand it and, Shake Up the Content
therefore, so clever. And, it’s very I used to be an LJ subscriber for years
easy to implement. and originally started reading your
magazines somewhere in the mid-
I’m looking forward to seeing 1990s. I used to enjoy reading and
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