Some Little Bits: April 2012

Sunday, April 29, 2012

Contained Javascript Library template

This Javascript template enables a library to be written in its own namespace and handle being included multiple times on a page.
It's based on Douglas Crockford's json2.js library.

var MyLibrary;
if (!MyLibrary) {
MyLibrary = {};
}

(function () {
//'use strict';
  if (typeof MyLibrary.myFunction !== 'function') {
MyLibrary.myFunction = function (arg1, arg2) {
   //...method body here...
   return true;
};
}
}());

Thursday, April 26, 2012

Enable IE F12 Dev Tools

New contract, new machine.....and the Internet Explorer F12 debug tools don't work for me.

This fixed it:

Run gpedit.msc
In the left pane, click on to expand Computer Configuration, Administrative Templates, Windows Components, Internet Explorer, and Toolbars.
In the right pane, double click on Turn off Developer Tools
Select Disabled

Arg, how I hate IE.

Saturday, April 21, 2012

SQL 2005/2008 Median function

This is this simplest SQL 2005/2008 Median function I've come across:

SELECT
(
(SELECT MAX(MyColumn) FROM
(SELECT TOP 50 PERCENT MyColumn FROM MyTable ORDER BY MyColumn) AS BottomHalf)
+
(SELECT MIN(MyColumn) FROM
(SELECT TOP 50 PERCENT MyColumn FROM MyTable ORDER BY MyColumn DESC) AS TopHalf)
) / 2 AS Median

Thanks Jeff Atwood!
http://stackoverflow.com/questions/1342898/function-to-calculate-median-in-sql-server

Friday, April 6, 2012

Installing Cloudera Hadoop 0.20 and Mahout on Ubuntu 11

Notes for installing Cloudera Hadoop 0.20 and Mahout on Ubuntu 11.10
April 2012

UPDATE SEPT 2014 - ok this is very old now. A better way is to just use the Cloudera CDH installer!
# wget http://archive.cloudera.com/cm5/installer/latest/cloudera-manager-installer.bin
# chmod u+x cloudera-manager-installer.bin
# sudo ./cloudera-manager-installer.bin
Then follow the local installer steps before navigating to the web installer when prompted.

Original April 2012 Instructions:

0. Ubuntu
Fresh install of Ubuntu ubuntu-11.10-desktop-amd64.iso on VirualBox with all updates and Guest Addons
Also mount a shared folder created in VirtualBox:
$ sudo mount -t vboxsf _Shared ~/_Shared
or add this line (without sudo) to /etc/rc.local

1. Java and ssh prerequisites:
http://cloudblog.8kmiles.com/2011/12/02/hadoop-prerequisite-for-hadoop-setup-in-ubuntu/
http://softwareinabottle.wordpress.com/2011/11/17/install-sun-jdk-6-on-ubuntu-11-10/

2. Update Java env by adding the following to: /etc/bash.bashrc
http://blog.sanaulla.info/2009/04/02/installing-jdk-setting-java_home-in-ubuntu/
JAVA_HOME=/usr/lib/jvm/java-6-sun
export JAVA_HOME
PATH=$PATH:$JAVA_HOME/bin:
export PATH
CLASSPATH=$JAVA_HOME/lib/:.
export CLASSPATH

3. CDH3 install hadoop core:
http://cloudblog.8kmiles.com/2011/12/06/hadoop-cdh3-setup-in-ubuntu/
3.1 create cloudera.list:
$ sudo pico /etc/apt/sources.list.d/cloudera.list
with content:
deb http://archive.cloudera.com/debian maverick-cdh3 contrib
deb-src http://archive.cloudera.com/debian maverick-cdh3 contrib
$ curl -s http://archive.cloudera.com/debian/archive.key | sudo apt-key add -
$ sudo apt-get update
$ sudo apt-get install hadoop-0.20
$ hadoop version

4. CDH3 install daemons for Pseudo Distributed Mode:
http://cloudblog.8kmiles.com/2011/12/07/hadoop-cdh3-pseudo-distributed-mode-setup/
to set up Standalone mode see: http://cloudblog.8kmiles.com/2011/12/07/hadoop-cdh3-standalone-mode-setup/

$ sudo apt-get install hadoop-0.20-namenode
$ sudo apt-get install hadoop-0.20-secondarynamenode
$ sudo apt-get install hadoop-0.20-jobtracker
$ sudo apt-get install hadoop-0.20-datanode
$ sudo apt-get install hadoop-0.20-tasktracker

$ sudo apt-get install hadoop-0.20-conf-pseudo
$ sudo alternatives --display hadoop-0.20-conf

5. Test the daemons:
for service in /etc/init.d/hadoop-0.20-*; do sudo $service start; done
sudo jps
hadoop jar /usr/lib/hadoop/hadoop-*-examples.jar pi 2 100000

Navigate to: http://localhost:50070/ for Namenode details
Navigate to: http://localhost:50030/ for Job details

for service in /etc/init.d/hadoop-0.20-*; do sudo $service stop; done

6. Install mahout:
http://cloudblog.8kmiles.com/2012/02/16/cdh3-mahout-setup/
$ sudo apt-get install mahout

7. Install Hue interface:
https://ccp.cloudera.com/display/CDHDOC/Hue+Installation#HueInstallation-Installing%2CConfiguring%2CandStartingHueonOneMachine
$ sudo apt-get install hue

Open the /etc/hue/hue.ini configuration file and add:
[desktop]
secret_key=jFE93j;2[280-eiw.tyXrN2s3['d:/.q[eI^^y#e=+Iei*@Mn<qW5o

$ for service in /etc/init.d/hadoop-0.20-*; do sudo $service start; done
sudo /etc/init.d/hue start
Navigate to: http://localhost:8088/ for Hue

I hope these notes and links help someone out. Please leave a comment if you have have any problems or additions.

Some Little Bits