Tapdancing Goats

A sinkhole the size of a city block swallowed a building in Guatemala on Sunday. This image is mind blowing.

Ten things about the Guatemalan sinkhole:

1. Art Bell will spend a month interviewing “experts” that claim this hole either goes to the center of the (hollow) Earth, was made by aliens, and/or is a portal to another dimension.

2. Can you buy sinkhole insurance?

3. Dude, I dare you to jump the hole on your bike. No it’s cool, I made this ramp.

4. I bet somebody was trying to dig a gold mine underneath the town, like in Paint Your Wagon.

5. Joss Whedon is already writing Buffy El Asesino Del Vampiro, a farcical tale of coming of age in Guatemala, plus vampires.

6. It’s Photoshopped, the reflections are all wrong.

7. Think everyone is pissed off at that blue store in the upper left, which suffered no visible damage even though it overhangs the hole?

8. Why didn’t this happen in New York when Alfred Beach was secretly digging a subway?

9. If this was Kansas City, they’d just put a steel plate over the hole and forget about it for six months.

10. Visit Guatemala! For all your ring disposal needs!

It looks like pilots and programmers have a lot in common:

The average pilot, despite the somewhat swaggering exterior, is very much capable of such feelings as love, affection, intimacy, and caring.

These feelings just don’t involve anyone else.

Found on a t-shirt

The alt text in today’s XKCD is a beautiful little poem.

Telescopes and bathyscapes
and sonar probes of Scottish lakes,
Tacoma Narrows bridge collapse
explained with abstract phase-space maps,
some x-ray slides, a music score,
Minard’s Napoleonic war:
the most exciting new frontier
is charting what’s already here.

I formatted the lines, so it might not scan the way Randall wanted. Tough.

This is the problem I have with Joss Whedon right here. All his properties are about loss of innocence and coming of age, and it just doesn’t work in an American TV show where the main story line can never be resolved and the characters can never quite get there. It worked in Dr. Horrible. Maybe with The Avengers, Whedon will break into movies and do shorter, closed story lines that actually work.

Puppet is an invaluable tool for managing a large number of Linux servers. By defining different classes for each service I deploy, I can easily define what runs on each server I control just by changing the site manifest.

A problem I ran into early when I was bringing services into Puppet was slightly different configurations on servers with different specs. For example, I run Tomcat on three servers but one is also running some other services. On this one server the JVM maximum heap size needs to be lower than on the others, but the rest of the Tomcat configuration is the same. To manage this without making a second class definition I used the template system in Puppet.

There are four steps to making this work. First you need to define a default for the variable. Next you need to write the template. Third, connect the template to a file on the client. Finally override the variable where you need it.

Read the rest…

Puppet is a system for replicating configurations to many servers, and it makes managing a Linux¹ server farm ridiculously easy. One server runs a master process, while the others run a client which connects to the master² to get the correct configuration. Clients are identified by hostname, so if your servers don’t have resolvable names you’ll need to put them in the hosts file on the master.

Puppet uses a declarative syntax built on top of ruby for defining rules. The documentation is mediocre at best, so you may struggle at first learning how to write the rules. Just read through the example recipes and test it out with a non-production server. The easiest way I found to test a rule is to run

sudo puppetd --test

on the server that should be getting the configuration. It will tell you there if there are any errors.

The version of puppet in Ubuntu 9.10 doesn’t support defining node names with regular expressions, so you might want to grab the version in Debian sid.

I’m still trying to figure out the best way to split up modules and organize my node definitions, so if you’ve used Puppet leave a comment and let me know what you think.

Bear Grylls‘s show is getting a little long in the tooth, and the staged “danger situations” are getting more and more ridiculous. I know exactly what Bear needs.

U.S. Marshals.

Every week Bear gets dropped in a wilderness location (like Les Stroud really did) and has to evade U.S. Marshals for seven days. The locals will be told that he’s a real fugitive. Set the dogs on him. Heck, they should shoot him on sight, just to add a bit more excitement. The real fun begins when Bear has to betray his camera crew to buy some more time.

My previous server was unexpectedly destroyed, but after a call to Joe we’re back up and better than ever. Now that I’m actually paying for my space, I’m inspired to dust off this old thing and give it a new go. I also have a lot more time now since I graduated last May.

I plan to start posting a wider variety of content rather than trying to stick to Linux, development, physics, and LaTeX. I’ve become more active on twitter and Facebook, so I’m dumping short stuff there. I also got a tumblr account as a temporary landing site while this one was down, and I think I’ll be keeping it for meaningless drivel that’s between tweet and blog length. I’ll lovingly handcraft longer, meatier, vastly more important drivel for this site. You’ll get more of my personality, my raw thoughts, and let’s be honest, I haven’t quite been prolific with the geeky material to date.

One step towards the personalization of my personal blog has been to import my old LiveJournal posts. These date back to the heady days of 2001 when “blog” was a new term that was still considered a contraction of “web log.” I was a freshly laid-off refugee of the dot-com bust back then, and I was still too dumb to know I’m not funny. There might be some gems in the archives, but as you dig through try not to get lost in the self-important ramblings of an arrogant young man. If the going is too tough, I promise to keep the site updated with a steady stream of self-important ramblings from an arrogant, slightly less young man.

So thanks for looking at the main site after you stumbled across one of my old LaTeX posts. I hope this isn’t the last update for another two years.

The Papervision3D wiki has an example for making billboarded sprites with just three extra lines of code. Trouble is, it doesn’t really work. Anyone who’s tried it may have noticed that when the planes get too close to the camera, or if the camera rotates around it’s z-axis at all, the planes start rolling instead of staying vertical.

The problem is that the lookAt method defaults to using the world y-axis as “up” for the billboards, which isn’t usually correct. Of course we don’t really care about the world y-axis with billboards. We just want them to be vertical in the camera. Here’s some code that does it.

I use LaTeX for all my physics homework and lab reports, and I’ll be using it for a master’s thesis in the next few years, so I’m constantly adding to my library of LaTeX commands to save some typing. Here’s a good one when you need to use scientific or engineering notation. Put the following in the document preamble (before \begin{document}):

Then, typing

gives you: The [111] crystal planes are 3.2×10^-10 m apart. whether or not you’re already in a math environment. If the exponent is just one number, you can omit the braces, like this: 3\e8 m/s. Cool, huh?

(Of course, for 10^-10 m you can just use Angstroms, \AA. If you’re in a math environment, use \text{\AA}, or else the circle won’t line up with the A. That is, if you’re okay with non-SI units.)