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MonadLUG notes, 11-October-2007: Ben Scott and DNS

By Ted Roche on October 27, 2007 in Linux, OpenSource, Technology

Late post: a great meeting Thursday night the 11th of October: thirteen people made it to the October meeting of the Monadnock Area Linux User Group, held as usual at the SAU #1 offices in Peterborough on the second Thursday at 7 PM. Thanks to Ken for sponsoring us at the offices, and dealing diplomatically with the double-booking of the space.

Ben had a little trouble finding the place, after a long, long drive from Dover. We forgot to mention in the driving directions which of the dozens of “Use other door” doors the meeting was held behind, so Ben had to find the Boy Scout meeting and the girls volleyball practices before finding us. Charlie promised to update the directions.

Nonplussed by all of this, Ben gave a great presentation on DNS, reprising his previous presentations. He’d replaced the MagicPoint presentation with S5, and had a few technical issues with getting it to behave, but persevered. I expect we’ll see an update to the slides on:

http://wiki.gnhlug.org/twiki2/bin/view/Www/PresentDNS

But the other files there (bind configuration files, sample inside and external zone files, etc.) should be relevant.

Ben gave a great overview of the Domain Name System and how it works from several client OSes, how the trail of DNS queries is processed, the structure of zone files, the structure of the BIND configuration files, and many of the common misconfigurations that lead to errors or just quiet failures.

It was a meeting well worth attending. Thanks to Ben for efforts above and beyond, to Charlie for hosting and managing the meeting, and to Ken and the SAU#1 offices for providing the facilities.

PySIG notes, 25-Oct-2007, Kent Johnson and Beautiful Soup sprint

By Ted Roche on October 26, 2007 in LAMP, OpenSource, Python, Technology

Thirteen people elected to skip watching the second game of the World Series (Go Sox!) to attend the October meeting of the Python Special Interest Group (PySIG), held as usual at the Amoskeag Business Incubator in Manchester, New Hampshire, on the fourth Thursday of the month, 7 PM until… well, 10 PM last night!

The usual slew of announcements was made: the PySIG won’t meet on the usual night due to the Thanksgiving holiday. A meeting might happen the week after, since there are five Thursdays. Stay tuned for the official announcement. Other affiliated GNHLUG meetings are posted to http://www.gnhlug.org and all are welcome.

I had proposed a programming challenge to PySIG: following recent discussions on the GNHLUG mailing lists about attendance at meetings, Jim Kuzdrall had suggested we more closely analyze the attendance data that’s been posted to the GNHLUG wiki [1] for the past two years or so. The data is accessible from there, but the HTML format is not too easy to manipulate into an analyze-able format.

Enter BeautifulSoup. BS is a utility written in Python that parses HTML, with a lot of toleration for somewhat malformed HTML, and produces a parsed tree that can be traversed or queried or parsed into its various elements. Kent S Johnson continued his great Kent’s Korner series with a presentation on the basics of using BeautifulSoup. Kent noted that the documentation on BS is remarkably good, with illustrative examples and exhaustive discussions. BS is in its third major version and continues to be supported by its original author.

After Kent’s Korner, Bill Sconce took the driver’s seat, set up BS on his machine and we began with the kernel of source Kent had supplied to parse the source. The group participated, suggested, yelled at typos, experimented, threw out code, started over, changed the angle of attack, and successfully produced code that not only parsed the existing page, but generated a comma-separated-value file with proper escaping, thanks to the csv module. Along the way, we discussed issued of character conversion (since BS uses the aptly-named UnicodeDammit module and csv wants ASCII), escaping issues, coding styles, and more.

At the end of the presentation, Kent got the projector again to show a somewhat different tack he had used to parse the HTML, with an emphasis on writing small functions to clean each column of the idiosyncracies found in the data (a “Saturday” in the date field, a date field a two-day event, approximated attendance ~24 and so forth) and generate some results: which groups had the highest attendance for the year? No one was surprised that Nashua/MerriLUG was #1, but who knew that PySIG was #2? Woo-hoo! We noted that RubySIG was last, but there’s a good sampling problem: they had just started up early in the year, and a couple attendance figures were missing.

To follow up from the meeting, we intended to merge Kent’s improvements into the group’s code and generate some CSV files that we can make available for download from the GNHLUG wiki for all to analyze, graph, visualize and study.

Thanks to Kent for preparing his Beautiful Soup presentation, to Bill Sconce and Alex Hewitt for arranging the meeting, to Bill again for having the patience to type while twelve people tsk’d at him, to the Amoskeag Business Incubator for providing the fine facilities, and to all for attending and vigorously participating in the meeting!

[1] which actually breaks down to:
http://wiki.gnhlug.org/twiki2/bin/view/Www/PastEvents2007,
http://wiki.gnhlug.org/twiki2/bin/view/Www/PastEvents2006, and
http://wiki.gnhlug.org/twiki2/bin/view/Www/PastEvents2005

Adding a “skin=print.pattern” eliminates some of the “chrome”
surrounding the content.

November 1: Real-Time Linux, Ed Haynes of Wind River, at DLSLUG

By Ted Roche on October 25, 2007 in Linux, OpenSource, Technology

The Dartmouth-Lake Sunapee Linux User Group will be hosting Ed Haynes of Wind River, presenting some of Wind River’s innovations on the Linux kernel to produce real-time Linux. Here’s the announcement from coordinator Bill McGonigle. Should be a fun meeting! Note the the meeting is held in Haldeman building, next door to our past location, in the lower level of the building.

Python Special Interest Group, Manchester, NH, 25-Oct-2007: Kent Johnson and Beautiful Soup

By Ted Roche on October 25, 2007 in LAMP, OpenSource, Python, Technology

The monthly meeting of the New Hampshire Python Special Interest Group takes place at the Amoskeag Business Incubator, Manchester, NH on 25 October 2007 (the 4th Thursday as usual) at 7:00PM. The Beginners’ session precedes at 6:30 PM. (Bring a Python question!)

Kent S. Johnson will be the featured speaker. Along with his regular Kent’s Korner presentation, we’re going to try hacking at some actual code problems tonight: using Beautiful Soup to parse a web page and produce some useful data. Should be interesting.

Organizer Bill Sconce posts the meeting announcement here.

New Hampshire Ruby, 16-Oct-2007: Rails Deployment

By Ted Roche on October 12, 2007 in LAMP, OpenSource, Ruby, Technology

Organizer Scott Garman posts:

This month’s NHRuby.org meeting topic will be on deploying Ruby on Rails applications. While back in May our meeting focus was on using Capistrano as our primary deployment tool, this month Scott Garman will be demonstrating a simpler application to manage Rails deployments, called “Vlad the Deployer”

Vlad the Deployer “targets the 80% use case” of deployments and boasts an engine written in less than 500 lines of code. Is simpler always better? Drop by our meeting and find out!

Scott will also be discussing various Rails-related tidbits he’s been working with recently.

Anyone who attends the meeting will be offered special coupon codes from Linode if they’re interested. The coupons give you two months of free service after purchasing one month of their Virtual Private Server (VPS) hosting. Linode sponsored the recent Rails Rumble and Nick Plante
had many good things to say about them.

WHEN: Tuesday, October 16, 2007. 7-9 PM.
WHERE: RMC Research Offices, 1000 Market Street, Portsmouth, NH.

For a map and driving directions, see our wiki site

CentraLUG notes, 1-October-2007: Michael Kazin on Nagios

By Ted Roche on October 2, 2007 in LAMP, Linux, OpenSource, Technology

Ten attendees made it to the October meeting of the Central NH Linux Group, coming from as far away as Nashua, Laconia, Peterborough and Hanover. CentraLUG is a chapter of the Greater New Hampshire Linux User Group, and our meeting was held as usual on the first Monday of the month at the New Hampshire Technical Institute‘s Library, Room 146, from 7 PM to 9 PM.

Michael Kazin presented Nagios, the host and service monitoring system. Michael told us a bit of his colorful personal history, and his exposure to Nagios as a student administrator of the Rutgers University computer center. He had found a neat diagram of the relationships between the configuration files in Nagios (we covered the current 2.x and not the 3.x, currently in beta) and went to explain how it could be used for businesses and home users, keeping an eye on working systems, alerting the operating to problematic conditions of low disk space, high CPU usage or unavailability of resources or services. Nagios has a huge number of pre-built modules, a 240-page manual, and documentation on how to extend the system for your own use.

Michael ended up with a presentation of a working Nagios installation on his home network, and showed how shutting down a service would set off an alarm, how the operator could flag the alarm as acknowledged, fix the problem, and verify that the alarm cleared. While the audience watched, participated and pestered Michael with questions, we identified and fixed a couple of permissions issues with his install and got the system to do things he’d never tried before. A good time was had by all. Wish you were there.

Michael’s slides are available on the GNHLUG site.

Bill Sconce was present to point out that modules could be written in Python. Ben Scott was heckled. I made the usual announcements: GNHLUG meetings can be found on http://www.gnhlug.org; several related meetings are taking place this month: SwANH’s annual infoeXchange, the NEARfest ham radio gathering. See the web site for links.

Thanks to Michael for a fine presentation, to Bill Sconce for providing the projector, to NHTI for providing the space and to all for attending and participating.

Red Hat Magazine | A guide to GNU Screen

By Ted Roche on September 28, 2007 in LAMP, Linux, OpenSource, Technology

A handy reference, A guide to GNU Screen, appears in Red Hat Magazine:

The same way tabbed browsing revolutionized the web experience, GNU Screen can do the same for your experience in the command line. GNU Screen allows you to manage several interactive shell instances within the same “window.”

The killer feature of screen, in my mind, is the ability to launch a long-running task, disconnect and reconnect to it later. For a consultant on the go, or when your wireless isn’t reliable (or the dog pulls the ethernet out of the wall), screen lets you reconnect and pick up where you left off. It’s handy for setting up a set of screens on a client site and then using only one secure tunnel to connect to them and examine the state of various applications. This is a tool everyone should learn and keep in their toolkit.

Notes from the NH Ruby/Rails Group, 25-Sept-2007: Scott Garman and Nick Plante

By Ted Roche on September 26, 2007 in LAMP, OpenSource, Ruby, Technology

Five attendees made it to the September meeting of the NH Ruby/Rails User Group, held as usual at the well-appointed RMC Research offices, though not on the usual third Tuesday. A round of introductions lead to some vigorous discussions, including how to broadcast and record meetings (perhaps a future meeting will be available via WebEx?), other computing organizations and conferences in the Granite State (GNHLUG, SwANH, the infoeXchange conference, NH High-Tech Council, etc.).

Nick Plante had some great stories about the Ruby Rampage, a 48-hour online programming contest he help run. A large number of teams competed and a fair number actually delivered working applications, some of them looking quite polished. There’s open voting on the most popular applications, and winners will walk away with a number of desirable prizes. Nick’s also been tapped to do the closing presentation at Ruby East, where he will demonstrate some of the more popular applications. There are some great apps there, and some will be providing their source code, though not all. Check them out!

On to the main presentation: Scott and Nick had started a simple Ruby app for NHRuby members to be able to suggest future meeting topics and vote on them, giving the organizers some ideas on what to present next. Tonight, Scott presented the unit, functional and integration test frameworks built into Rails and/or available as add-ons. Nick showed the UI for the voting interface and dove deep into how the form functioned. There was a lot of discussion, with debates on where the boundaries are in unit vs. functional vs. integration, and how Javascript (via the Prototype libraries) can be integrated into the interface and how Rails allows graceful degradation on platforms with Javascript unavailable or disabled. Comparisons were made between the internal, programmer-centric tests provided by Rails and external tests a QA person might run with a tool like Selenium. Lots and lots of great ideas. In a future meeting, Scott and Nick will discuss the next step, deploying the application, perhaps using Vlad the Deployer (ow) and/or the new Capistrano 2.

Thanks to Scott for organizing the meeting, Tim of RMC for providing the meeting space, Scott and Nick for the presentation, Brian for mentioning Selenium and all for their attendance and participation!

New Hampshire Ruby/Rails Group, 25-Sept-2007: Live Coding

By Ted Roche on September 24, 2007 in LAMP, OpenSource, Ruby, Technology

Organizer Scott Garmin posts:

“Tomorrow’s NH Ruby/Rails User Group meeting will include a continuation of the live coding project Nick Plante and Scott Garman started during the July meeting. This project was to develop a web application where group members could submit proposed topics for future meetings, and vote on their favorites… This month, Nick Plante will demonstrate how to add the voting system to the application. Nick will use an AJAX-based 5-star voting system that you may have seen on many product review sites… Scott Garman will give an introduction to the Rails testing framework, demonstrating how unit, functional, and integration tests are written. Scott will also demo some useful third-party tools that make testing easier and faster, and how they integrate with the NetBeans IDE.”

WHEN: Tuesday, September 25, 2007. 7-9 PM.
WHERE: RMC Research Offices, 1000 Market Street, Portsmouth, NH.

For a map and driving directions, see our wiki site.

CentraLUG: 1-Oct-2007: Michael Kazin shows Nagios

By Ted Roche on September 24, 2007 in CSS, LAMP, Linux, OpenSource, Ruby, Technology

The Central NH Linux User Group returns to the Library after a summer hiatus at the Sybase offices in Concord. The monthly meeting of CentraLUG, the Concord/Central NH GNHLUG chapter, happens the first Monday of most months at the New Hampshire Technical Institute‘s Library, room 146, at 7 PM. Next month’s meeting is on October 1st at 7 PM. Directions and maps are available at http://www.centralug.org Open to the public. Free admission. Tell your friends.

At this meeting, Michael Kazin will be presenting Nagios, the Open Source monitoring service. From http://www.nagios.org, “Nagios® is an Open Source host, service and network monitoring program.” Written in Perl and controlled by text configuration files, Nagios offers the ability to alert administrators to a huge number of possible problems with connectivity, speed, or performance. Nagios offers a web interface for close-to-real-time monitoring, email/pager alerts, the ability to launch other programs, etc.”

Michael is a computer consultant at a well-known consultancy working for well-known companies in the military-industrial complex. He is a member of the Greater New Hampshire Linux User Group’s Board of Directors. Previously, Michael helped run the Rutgers University Student Linux User Group and gained his experience with Nagios by monitoring hundreds of machines in the Rutgers Data Center.

Future Meetings: Currently, we have a couple interesting meetings coming up: November: Ted Roche on Cascading Style Sheets, December: David Berube on Ruby, January: Bruce Dawson on low-power Linux computers. As always, meetings are subject to change. You are encouraged to join the low-traffic announcement list to get announcement and cancellation information.

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