Ted Roche's weblog

It took 4 ThinkPads, 3 DVDs, two CDs, a Flash Drive and an iMac to make it through the day. No partridge. Tomorrow, five golden rings?

The Thinkpads: T61 is the primary workstation, but was suffering from SMART-reported disk drive errors and I spent half the day following the awesome instructions for bad block HOWTO for smartmontools to rescue the disk. In the meantime, the T41 served as backup workstation letting me surf, check email, etc. In the afternoon, the A31p has a legacy WinXP/IE7 install I can VNC into to test a client project. Meanwhile, I was also working on the Lenovo ThinkPad W700 to finally fix the running-out-of-disk-space problem thanks to System Restore, now disabled (thanks, System Restore! pffft!). Why do people keep using Windows?

The three DVDs were to burn the System Restore disks once there was a machine worth restoring.

The two CDs were something old and something new. I tried a Knoppix 5.11 CD to boot the W700 so I could do a partimage copy of the Vista OS partition where we’ve installed custom software for client testing. For some reason, the older Knoppix couldn’t handle the hardware and would fail to start. I grabbed the latest Knoppix, 6.2 (make sure you grab the November 18th or later image) and – whoa! – what a difference. The 6.x series is based on different software and uses LXDE as the default desktop — very slick!

I used the iMac to burn the CD. The most recent software on the T61, Fedora 11, seems to be confused about whether I have a CD-R on the machine or not, and I haven’t been able to burn a disk for a while.

I used the second CD (in the T61) to burn an image onto a 1Gb USB Flash drive . The Knoppix 6.2 comes with a built-in option to create the USB with a mouse click or two. It boots fast, has 284 Mb left over to preserve settings, and boots in the W700.

Brian Turnbull and Nick Plante each had excellent presentations for the New Hampshire Ruby Rails Group’s first meeting on the third Monday of the month, our new “regular meeting day.” (We won’t be having a December meeting, however; have a happy Kwanzaa, Hanukkah, Christmas, Saturnalia, Winter Solstice or non-denominational generic shopping holiday of your choice.)

Brian was up first, and talked about rvm, the Ruby Version Manager (slides here: http://www.slideshare.net/bturnbull/rvm-nhruby-nov-2009). RVM doesn’t just allow you to have multiple versions of ruby on your machine; you’ve always been able to do that with side-by-side installs or linking or aliases or other kludges. RVM can be found at https://rvm.io/ and can be installed as a Gem, from the Git repository or as a tarball. It’s not Ruby code, actually, but shell scripts, and it allows not just switching of the current active version of ruby, but much more interestingly, the entire set of gems associated with a version! Multiple gemsets can be assigned an alias that lets you group your gems by function or project or client. RVM also provides a facility to dump the list of gems from one version or gemset and load it into another, allowing you to test out the migration of an existing system to a new version with much less hassle. Finally, rvm also lets you invoke multiple versions serially, passing them a command like “rvm 1.86, 1.8.7, 1.9.1 rake spec” where rvm will run all your tests on multiple versions and report results, even in JSON if specified. This could be the core of a really simple Continuous Integration (CI) server in a single line of code!

Brian cautioned that rvm is early in its development cycle (current as of last night was 0.0.79) and changes are coming fast and furious, but it’s worth taking some time to keep track of this very interesting development!

Brian also mentioned that rvm has some extensions to work with Bundler. Nick mentioned that Bundler, a project from Yehuda Katz (core contributor to both Ruby and jQuery) , is slated to become the default means of managing gems in Rails 3.0. Here’s a good link to learn more: http://yehudakatz.com/2009/11/03/using-the-new-gem-bundler-today/

Nick Plante was up next, with his presentation on EC2 for Rails Development (http://zapnap.github.com/presentations/ec2-rubber/#0). Nick talked about the evolution of deployment of Rails (or Rack) solutions, moving from very painful to much easier with the introduction of Capistrano (http://www.capistranorb.com/). He reviewed how simple it was to deploy an application with Capistrano, and then talked about the power of the Amazon Web Services (AWS) http://aws.amazon.com/ and Cloud Computing in general. Capistrano is focused on general deployment to a server, but the new add-on, Rubber (http://github.com/wr0ngway/rubber),  extends that to work with elastic computing resources like AWS’ Elastic Compute Cloud (EC2). We walked through the basics of the install-configure-deploy scenario and then “Insert Demo Here.” – he did it. Defying the Demo Gods (who had already tortured Brian a bit), Nick grabbed a copy of RedMine (http://www.redmine.org/) from GitHub, did the couple of minor configuration items needed to make it work locally (creating the session key, copying the sample database config to the live one, setting it to use SQLite3 locally and running db:migrate) and then set it up for deployment: first invoking Capistrano (doing some configuring) and then Vulcanizing (how else would you make rubber) the installation, then deploying it to a brand-new AWS instance. The steps flew by lightening-fast: the Amazon instance was up and running a minute after being invoked, then took a couple of minutes to install and configure Apache, Passenger, MySQL, the Redmine application, and sftp the development directory files to the instance. Within a few minutes, Nick could browse the machine and see the running application as well as ssh into the box and make any changes. There are innumerable options, of course, but they are all accessible by reviewing the configuration files and the source to tune it to your particular needs.

While we waited for the installation to complete, I brought up some of the customer’s concerns and practitioner’s insights from last Thursday’s MonadLUG meeting on Cloud Computing and we talked about how those applied. I expressed concerns about how persistent data storage worked, since the cloud images were considered ephemeral. Nick pointed out that the instance, while running could have a local database and it could be in a master-slave replication arrangement with either another instance (within the AWS, there aren’t bandwidth charges) or a hosted or local machine. Also mentioned was the Amazon Relation Database Service (RDS), which can provide a MySQL database instance with backups. So, there are lots of options.

Thanks to Brian and Nick for excellent presentations as well as organizing the meeting and bringing the pizza, to Tim and the folks at RMC Research for providing the excellent facilites and to all eleven who attended and participated in the meeting.

Remember, no Ruby meeting meeting in December. Stay tuned for a January announcement.

Reposting Nick’s announcement from http://nhruby.org/2009/11/8/november-meetup-ec2-and-rvm:

NHRuby is meeting for the last time this year on Monday the 16th at 7pm at RMC Research, 1000 Market Street, Building 2, Portsmouth, NH. Monday?! You say? Yes — due to scheduling conflicts, the regular meeting day for NHRuby is now to the third Monday of the month. Also, since next month’s meeting fell so close to the Christmas holiday, we decided to skip the December meetup and resume in January. So join us for the last meeting of 2009 for two presentations by NHRuby regulars, Nick Plante and Brian Turnbull.

Nick will present EC2, Amazon’s Elastic Compute Cloud. EC2 is a web service which allows customers to rent virtual server instances by the hour. The real power of EC2 is that it allows you to auto-scale your web applications on demand. Expecting heavy load today? Fire up another web app server or two, with no wait time for procurement, while taking advantage of Amazon’s robust infrastructure.

Making EC2 even more attractive are tools like Matt Conway’s Rubber, a set of extensions to Capistrano that allows you to script procurement and provisioning of server instances as well as deployment of your application itself. Need to set up a staging server? Use Rubber to deploy a disk image, install the necessary stack and utilities, and deploy the appropriate version of your application — in moments — all automatically. In this talk, Nick will quickly discuss the basics you need to know and then dive right into a realtime demo.

Brian will introduce RVM, the Ruby Version Manager. RVM is a command line tool which allows us to easily install, manage, and work with multiple Ruby environments and sets of gems. Topics to be covered include:

• Installation of RVM on Linux or OS X.
• Day to day use of RVM to switch between Ruby interpreters
• Managing sets of gems using Named Gem Sets

If you’ve ever been burned by differences between development and production, you should check out RVM — see how easy it is to take control of your Ruby environment.

So join us on Monday, 16 November at RMC Research for the last meeting of the year. Hope to see you there!

I think I saw this written up in one of ACM‘s magazines, but those don’t get a lot of traffic, and they hide much of their best content behind subscriber-only firewalls. NPR did a story over the weekend on a group at Stanford doing “computational photography” – camera hardware with a Linux backend. I’ve been a fan of photography for decades, since Dad and I set up a dark room in the cellar. The Stanford prototypes are ungainly, of course, but the potential is very interesting. Here’s the story and the linked video. While you wouldn’t like to lug the prototype around all day on a neck strap, the idea of a “smart” camera where you could develop (or download) new effects, hacks, etc. and upgrade the capabilities of your camera is very attractive. Like the consumer cellular telephones started out as fixed devices and added uploadable ringtones, then backgrounds, then camera effects, then wide-open platforms like Google’s Android phone, an open hardware platform for photography could create an entire new category of devices.