Friday, September 19, 2014

Guaranteed minimum income?

Seeing this MetaFilter post, I wonder if we're starting to approach Gandhicon 3 ("then they fight you") on the idea of a guaranteed minimum income.

I sincerely hope so. I honestly don't know if it's a good idea or not, but it would be great to see it discussed seriously. (And seeing it brought up in The Atlantic and actually kicked around in Switzerland seems like a good step in that direction.)

Intuitively, it seems... unwise.  Wouldn't everyone just stop working, letting the world grind to a halt?  But there are indications that when it was tried in Canada, that wasn't the case, with hours worked dropping only about 1% for men and between 3-5% for women, while hospitalizations decreased and school attendance increased.

(On the gripping hand, I may have been heavily influenced by being raised Orthodox Trekkie.)

I suspect this will become more and more of an issue as jobs continue to be lost to automation.  When self-driving cars are common, will we still have truckers?  That's 3.5 million jobs in the US alone.  And then there are the taxi drivers, bus drivers, etc.  And that's just one industry.

Something to think about.

Sunday, July 20, 2014

Using Netflix in XBMC with Ubuntu 14.04

I use XBMC to run my home theater system.  It's a great piece of software that can be configured to look and act in a huge variety of ways while remaining straightforward to use and set up.  One of its great features is an add-on system with a rich set of third-party multimedia tools.

Until recently, it was pretty straightforward to have a nice experience in XBMC under Linux using a combination of XBMCFlix and Pipelight.  Pipelight provides a way to run the Silverlight video streaming libraries under Linux and XBMCFlix launches the Netflix player in a full-screen Chrome window.  Installing these add-ons meant that Netflix worked well[1] and integrated right into XBMC.

Recently, however, Google has dropped support for the Netscape Plugin API (NPAPI) which Pipelight relies on to make Silverlight work.  Since XBMCFlix launches Chrome and can't be configured to use Firefox, this means that upgrading to a recent version of Chrome breaks Netflix support in XBMC on Linux.

Fortunately it's easy to work around this and trick the Chrome launcher used by XBMC to use Firefox instead.  It's a dirty hack and isn't a great solution for a general purpose desktop (especially as it involves uninstalling Chrome, which you might want to keep) but it does the trick on my entertainment system.

Here's how to do it:

  1. Uninstall Chrome or Chromium.  (On Ubuntu or other Debian-based distribution, you can do this in the Software Center or by typing "sudo apt-get remove google-chrome" (or "sudo apt-get remove chromium-browser" in a terminal.)
  2. Launch Firefox, put it in full-screen mode by pressing F11, and exit it with Alt-F4.  This will make it default to full-screen next time it's launched.
  3. Using your favorite text editor, create a script in your home directory called "google-chrome".  (It's important to make it all lower case and include the hyphen.  It needs to be named exactly "google-chrome", nothing else.)
  4. Copy and paste the following into the text file:


    for i in $@; do
        if [[ $i =~ ^http ]]
          urls="$urls $i"

    firefox $urls
  5. Save the file.
  6. Make your script executable so it can be launched by XBMC by opening a terminal and typing "chmod a+x google-chrome".
  7. Put your script where the launcher for Chrome would normally live by typing "sudo mv google-chrome /usr/bin".
Once this is done, you can install Pipelight and XBMCFlix in XBMC as you normally would.  When XBMCFlix goes to launch Chrome, it will launch Firefox instead.

Again, this is a bit of an ugly hack, but if you have a PC that does nothing but run XBMC this will get you up and working quickly.  There are ways that a script like this could be exploited, but the odds of Netflix including one in a URL to target Linux users of XBMC are pretty low, and if you have a single-purpose home theater system there's probably not much damage that could be done anyway.

Now go enjoy some movies!

1: Well, after you lie to Netflix about what operating system you're running. It's 2014 and they are still doing browser user-agent sniffing as if it were useful or effective.

Sunday, March 30, 2014

Adding hardware support to MAAS

MAAS and power

MAAS, or Metal as a Service, is a tool for treating physical servers similarly to cloud resources.  It lets you take a pile of hardware and assign workloads to it without worrying about all the support infrastructure underneath.  In effect, you can plug a bunch of systems into a network and have a Hadoop or OpenStack cluster up, running, and properly configured inside of half an hour.  It's really cool stuff.

But MAAS is targeted at enterprise-level hardware.  It expects things like IPMI to be available to control the hardware at a basic level.  (If your tool is going to be installing an operating system onto a computer, it needs to be able to control that computer at a level below the OS.)  I have a stack of older desktops sitting around gathering dust that I wanted to use as a cluster for experimenting at home.  They still function quite well, but being desktops they don't have enterprise features like IPMI.

Fortunately most desktop BIOSes have a setting to control what they do after a power outage.  Crucially, they can be set to turn the system on when electrical power is restored, regardless of whether the system was on or off when power was lost.  This means I could use an externally controlled power switch in place of IPMI to allow MAAS to power my desktops on and off.

Power on after power failure.  (Helpfully hidden under a random submenu in the BIOS rather than under the 'POWER SETTINGS' heading.)

I used the Web Power Switch 7 from Digital Loggers for this project.  (Warning: almost every page on their site has autoplaying audio and/or video.  Ugh.)  I'll be completely honest here -- price was the reason I chose this switch.  It allows control of up to 8 outlets and cost me just under $140 from Amazon.

My shiny new power switch.  (What do you mean, your datacenter doesn't have an oriental rug?)

Power templates

There are a few bits of MAAS that I had to touch to fully enable support for my DLI switch.  The first and most obvious was creating a power control template to tell MAAS how to talk to the switch.

When MAAS is installed, the templates that tell it how to talk to power management systems are put in /etc/maas/templates/power.  These are shell scripts with a bit of Python evaluation and substitution (surrounded by {{double braces}})that MAAS uses at runtime to build a command to control a specific system.  There are several examples to use there already, and these can be modified to suit your environment.  For example, the SeaMicro SM15000 hardware template looks like this:

# -*- mode: shell-script -*-
# Control a system via ipmipower, sending the seamicro specific hex codes
{{py: power_mode = 1 if power_change == 'on' else 6 }}

{{ipmitool}} -I lanplus \
    -H {{power_address}} -U {{power_user}} \
    -P {{power_pass}} raw 0x2E 1 0x00 0x7d 0xab \
    {{power_mode}} 0 {{system_id}}

I started by simply replacing one of these templates with my own code.  Because the DLI Web Power Switch can be controlled via HTTP, I just needed to build a GET request for the outlet I wanted to control and send it to the switch, like this:

# -*- mode: shell-script -*-
# Control a system via the Digital Loggers, Inc. RESTful interface
{{py: power_mode = 'ON' if power_change == 'on' else 'OFF' }}

wget --auth-no-challenge -O /dev/null \

Once I had this template replacing the original sm15k template, I was able to control my switch by telling MAAS I had SeaMicro hardware.  Success!

Better integration

I could have stopped there with a working system.  But it bothered me a bit to lie to MAAS about my hardware.  And what if someday I or someone else wanted to mix the DLI switch with actual SeaMicro hardware?  Replacing the sm15k template with my DLI template wouldn't work then.

It turns out that there are two places in the MAAS code that need to be modified to make it aware of a new power switch.  In the MAAS source, these are src/maasserver/ and src/provisioningserver/ is where the real definition of a new power switch is; just needs an entry in two lists to make the UI show the switch as an option.  (There's a comment in to the effect that adding the switch name in it will not be necessary at some point in the future, but at least as of March 2014 it still is.)

The code needed to add a power switch is straightforward.  Provide the variables the switch will need to operate a system (e.g. outlet number, IP address of the switch, credentials, etc.) and give them names that can be referenced in the power template later.


The code I added can be seen in Launchpad (click "expand all" to see the diffs).

Once I added the code there, I was able to rebuild MAAS and see my new switch as an option.  It all works, and now my old desktops have new life!