GNU/Linux

Some GNU/Linux desktop deployments require secure authentication from a Windows Active Directory server. Gerald Carter, a long-time member of the Samba team and an enthusiastic free software developer, now works for Likewise. You can learn from this discussion if you are considering becoming a software developer, are looking for a good business model for your free software-based company, or are looking to manage your network more securely.

My dad has been pestering me for some time to find him an open source tool that he could use to follow the market trends. He's been thinking about investing a little something in the market, but not without due diligence. Grism, written in Ruby, is the tool my dad now uses to easily follow the changing market trends. It allows you to create watchlists and portfolios and offers charts to help you gauge the performance of particular stocks.

Read more of this story at Slashdot.

Read more of this story at Slashdot.

A cellular plan using an EVDO modem can provide a connection with bandwidth of approximately 3Mbps to the client and 1.5Mbps up to the provider (comparable to DSL) for a much lower cost than alternatives such as satellite. For applications requiring high-quality audio transmission from remote locations, such as the radio remotes we do at the radio station where I work, a Linux laptop with an EVDO modem and VoIP software offers an inexpensive and reliable solution. Here's what you need to get started.

If you're a frequent business traveler who keeps important company files on your laptop, using a centralized management solution to back up files automatically during a fixed time interval won't work. Instead, consider Box Backup, which backs up files from a laptop directly to a backup server over an encrypted link.

The title alone is a mouthful, but you have to love a book that knows what it’s about.

‘Unix and Linux Systems Administration’. We all know what that is. Balding, bearded, bespectacled wizards wearing t-shirts, nestled deep in a corporate office, on a floor the CEO and VP’s never visit, tapping out incantations day and night, feeding the temperamental beasts caged in the data center.

No? What about a growing group of dedicated, professional, hard-working experts who keep servers–and consequently the rest of the business–running smoothly? Sure, some of them may have less than a full head of hair, or wear the occasional t-shirt to work, but if your job (which you only call ‘System Administrator’ on your resume) involves monitoring and maintaining expensive hardware that performs critical business functions, and if the CEO only notices you or your group when things have going horribly, horribly wrong… then this is the book for you.

Back up a bit. How did ‘Python’ sneak into the title? This is a book for System Administrators–I mean, sysadmins. These guys write bash scripts to do their laundry. Sure, some of them may have joined the cult of Perl, and what proper Linux shop doesn’t have a zsh fanatic locked in the supply closet (in case of emergency)?

Unless you’ve been asleep at the keyboard for a few years, it’s hard to miss the rise of Python as a language of choice among web developers–along with old favorites Perl, PHP, and Java, and the new kid on the block, Ruby.

Perl is an old standby for many sysadmins, especially in those moments when you realize there’s a CPAN module that does 90% of what you need, or you’re tired of guessing whether brackets should go around the test condition in an ‘if’ statement. Is Python ready to take it’s place alongside Perl in a sysadmin’s toolbox? The authors of this book make an excellent case that yes, it is.

The first chapter starts with some exposition and justification, then segues into a comparison of simple code examples using bash, Perl, and Python. A tour of python using the IPython interactive shell fills out the rest of the chapter. This section, which is skippable for those with python experience and not systematic or detailed enough to count as a true tutorial, gives the reader a taste of the example-based approach of the rest of the book and a gentle introduction to Python syntax and the Python shell.

The second chapter, the longest in the book, dives into the Ipython shell in detail, including more detailed instructions for installation. These might have been better placed before the interactive examples in the previous chapter.

Chapter two then proceeds to describe IPython and many of its features in detail, and will probably teach even experienced IPython users some new tricks. While the authors are correct to tout the impressive power of IPython, I question the wisdom of including such a detailed tutorial this early in the book. As useful as IPython is, there is a lot of material for readers to work through here that distracts from the book’s true focus. Much of this material may have been better introduced later on, or relegated to a final chapter or appendix. Strangely, there is no corresponding material introducing the Python language itself. There are, however, plenty of resources available online and in book form for those looking for a more thorough introduction to Python.

The third chapter gives some concrete examples of data gathering and reporting. It covers subjects as diverse as processing log files, sending and receiving email, and generating charts and reports, providing an excellent overview of some useful Python modules.

However, the need for a more in-depth tutorial to Python becomes apparent in this and future chapters. Previous chapters emphasize the usefulness of creating and using custom modules, and this chapter offers some building blocks from which readers could begin to create such a library. However, not enough information is provided about module creation; most readers would not yet be comfortable creating and using their own modules.

Chapter eight discusses creating python eggs, and chapter one describes how modules are imported, but nothing between the two (such as how Python treats a directory containing an __init__.py file when loading modules) is covered. Similarly, concepts such as regular expressions, list comprehensions, and exception handling are presented in example code throughout the book with little or no comment or explanation.

The fourth chapter reviews most of the primary networking modules in the python core library, starting with the low level socket module and proceeding up the stack through
urllib and urllib2. It then documents the usage of more specialized modules, such as Pyro as an XMLRPC replacement, paramiko for SSH support, Twisted for event-driven networking code, and Scapy for interactive and scripted packet-level network introspection.

The next two chapters follow the same pattern established in chapter four. Chapter five, rather ambitiously named ‘Data,’ is really about file and directory manipulation, and gives a good introduction to the same. Chapter six covers SNMP programming in similar detail.

Chapter seven returns to the formula of chapter three, and starts with the broad goal of cross-platform management, and guides the user through the implementation of a multi-threaded ssh-based command dispatch tool. It then describes using the PyInotify module to monitor filesystem changes.

Chapter seven then switches gears , discussing several techniques for use with OS X systems, then lightly touching on Red Hat-based technologies, Ubuntu, and Solaris. Next, it covers virtualization, followed by cloud computing with Amazon and Google. Finally, it describes using Zenoss to manage Windows systems.

Chapter eight covers installing Python packages using setuptools and Easy Install, and then moves on to creating and distributing Python packages with setuptools and distutils.

Chapter nine discusses process management and threading, including recipes for proper threading and daemonizing processes. Chapter ten covers the basics of creating simple GUIs, for both traditional and web-based applications. Chapter eleven covers data persistence in similar detail, starting with the pickle, shelve, and yaml modules, and moving quickly into sqlite and ORM with storm and sqlalchemy.
Chapter twelve provides an equally thorough introduction to making python scripts run well on the command line.

Chapter thirteen seems a bit out of place, as it is a discussion of callbacks, a fairly esoteric (though useful) feature of Python. If the authors are going to devote a chapter to this feature, why is there barely any mention of most of the other Python features used throughout the book?

Chapter fourteen is back on track, however, with simple but useful examples for managing DNS, using LDAP, another try at Apache log parsing, and a simple FTP mirror program.

Overall, this book provides a grand tour of core and optional Python modules that are likely to be useful for a sysadmin, along with a bevy of practical examples.

However, this book does not–by itself–serve as an introduction to Python for sysadmins. It skims over many important basics of the language.

Those already familiar with Python will get the most out of this book. If not, I’d recommend purchasing a beginner’s Python book as a companion, or you can rely on the many online Python tutorials and extensive documentation.

Similarly, while the book mentions writing and importing your own modules, and even using Python eggs and distutils to package and distribute them, a true stones-to-soup guide for creating and maintaining a library of useful modules is missing.

These caveats aside, if the reader has already acquired the basics of Python from another source, then Python For Unix and Linux System Administrators is likely to provide plenty of inspiration and guidance.

Note: One of the book’s authors, Noah Gift, is a frequent contributor to Red Hat Magazine.

The purpose of the Free Software Foundation (FSF) is probably obvious from its name -- but what does promoting free software mean in terms of everyday activity? Examining the roles of the organization shows how complex the FSF's advocacy role has become. It also reveals the range of services available to the free software community, and helps to explain how such a small group has had such a major influence on computer technology.

Project Gutenberg, the online library of more than 25,000 free books, is a treasure trove for bookworms and casual readers alike, but turning electronic text files into a readable form is not as easy as it may seem. In theory, since etexts are just plain text files, you should be able to open and read them on any platform without any tweaking. In practice, however, this approach rarely works. Hard line breaks, for example, may ruin the text flow, making it virtually impossible to read the book on a mobile device. Another problem is that most books are stored as single files, so locating a particular chapter or section in a lengthy book can be a serious nuisance. Then there are minor but annoying formatting quirks, such as inconsistent handling of italicized text, use of straight quotes instead of smart ones, and so on.

This month saw the release of LyX 1.6 release candidate 1. Occupying a position somewhere between a word processor and a mark-up editor, LyX is designed to meet the needs of professional and academic writers by allowing them to focus on their content rather than formatting and layout. It achieves this by eschewing some of the WYSIWYG conventions of a word processor. We've covered LyX in the past, so this time we'll focus on the enhancements that the 1.6 release brings with it.

Twitter is a social networking platform that keeps you in conversation by allowing you and your friends to follow each others' updates. The service lets users post and read 140-character updates, called tweets. With Twitter, you can do social networking on the fly, from your mobile phone or at your desktop, from a Web browser or a Twitter client. Twitter clients make the service more usuable by automatically checking for updates from your friends and allowing you to easily post your own updates. I tested four Twitter clients for Linux on a desktop running Ubuntu Hardy Heron.

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Question: After downloading and burning ISO files from Red Hat Network (RHN) why will the system not boot from the first burned CD?

Answer:

First, make sure that you have downloaded the correct files. For each distribution there are binary files and source files. To complete an installation the four binary files for a particular distribution are required.

Simply burning these files to CD as files will result in a single file being burnt to CD with a .iso extension. If this occurs your disks will not be bootable. The files available from Red Hat Network (RHN) are disk images and need to be burned to CD as an image.

Your burning software will extract the files from the .iso and burn them to CD. See your specific burning software documentation for more information on how to burn images to CD.

To check if you have burned each image correctly, simply examine the contents of the CD. Instead of a single .iso file the disk should contain multiple files and directories.

Red Hat’s customer service and support teams receive technical support questions from users all over the world. Red Hat technicians add the questions and answers to Red Hat Knowledgebase on a daily basis. Access to Red Hat Knowledgebase is free. Red Hat Magazine offers a preview into the Red Hat Knowledgebase by highlighting some of the most recent entries. The information provided in this article is for your information only. The origin of this information may be internal or external to Red Hat. While Red Hat attempts to verify the validity of this information before it is posted, Red Hat makes no express or implied claims to its validity.

Voiceroute, a software PBX vendor, originally started as a proprietary software company but went (at least partly) open source earlier this year. In this video, CEO Ming Guang Yong says the company should have moved toward open source "a lot sooner," and explains why. He and CTO Navin Kumar also talk about some of the specific differences between their open source and proprietary versions, including how and where they draw the line between the two, and share their thoughts about dealing with open source developers and building a successful open source development community.

One of the goals of the Software Freedom Law Center (SFLC) is to become a center for education in free and open source software (FOSS) legal issues. As part of this effort, the SFLC has already published "A Legal Issues Primer for Open Source and Free Software Projects." Its latest effort in public education, released last week, is "A Practical Guide to GPL Compliance," a 15-page guide for FOSS projects on how to avoid violations of the GNU General Public License (GPL) and Lesser General Public License (LGPL). The guide is a practical summary of its subject, but its wording is unnecessarily legalistic, and its structure and omissions sometimes fall short of the goal of being a standalone reference.

No one saw this coming. Cisco, the networking giant, announced today it was buying PostPath, maker of the Linux-based Exchange server replacement PostPath Server.