Setting up Apache Hadoop on RHEL6/CentOS 6

Setting up Apache Hadoop on RHEL6/CentOS 6 is simple wiith the recent availability of RPMs for Apache Hadoop it makes it much simpler to setup a basic Hadoop cluster. This will allow you to focus on how to use the features instead of having to learn how they were implemented.

These instructions DO NOT Hadoop settings to make Hadoop fast but it will get you running a Hadoop culster fast. We will leave Hadoop optimization for another day.

Installing Java JRE and JDK version 1.7(1.6) on CentOS 6 and config the system alternatives for "java"

You should simply use the packages from Sun.

Step (1) : Visit Sun’s web site and download the latest version of Java (the *.bin file not the *-rpm.bin) (

(pay close attention if you want the 32bit or 64bit version)

Example the 64-bit version of the JDK can be found at

Configure Sendmail as a Smarthost and rewriting the from-address

  1. Install both the sendmail and sendmail-cf packages on your Redhat/CentOs server.  Use the command: yum install sendmail sendmail-cf 
  2. To automatically start sendmail to start on system boot we issue the command: chkconfig sendmail on 
  3. To start sendmail NOW we issue the command: service sendmail start 

Creating a Centralized Syslog Server

A centralized syslog server was one of the first true SysAdmin tasks that I was given as a Linux Administrator way back in 1997. My boss at the time wanted to pull in log files from various appliances and have me use regexp to search them for certain key words. At the time Linux was still in its infancy, and I had just been dabbling with it in my free time. So, I jumped at the chance to introduce Linux to the company that I had worked for. Did it work? You bet it did!

How to Fix a "JVM terminated. Exit code=13" Error in Eclipse

    • First, realize that this error is caused when you are attempting to start Eclipse using the wrong version of the Java Virtual Machine (JVM). So you need to realize what JVM you are starting with.
    • If you are using Linux, you can type "which java" on the command line. Otherwise, you can type "java -version". This will give you the Java version.

Dell PowerEdge Server, Windows 2003 x64, and the Battle Over SAS RAID Drivers

It seemed like a simple enough task – Install Windows Server 2003 R2 Standard on a Dell PowerEdge 860.The server contains four 73GB SAS drives plugged into an internal PERC 5/i SAS RAID controller.The problem started out being that the Windows installer didn’t see the system’s hard drives during the setup process.

Fix for Windows Server 2003 Setup No OEM Drivers

Fix for Windows Server 2003 Setup error: “Setup could not find a floppy drive on your machine to load OEM driver from floppy disk”

Windows Server 2003 R2 32-bit setup error when specifying additional storage drivers:

“Setup could not find a floppy drive on your machine to load OEM driver from floppy disk

Press ESC to Cancel loading OEM Drivers
Press F3 to quit setup”

This error occured when trying to install Windows Server 2003 R2 onto a Dell PowerEdge 830 server with a Dell CERC SATA 1.5/6ch RAID controller card.

Recover/Reset Windows 2003 Server Active Directory Administrator Password

This article assumes that you forgot the AD admin password, someone changed it on you, or you are recovering from an attack.

This is not meant as a how to hack your company’s Active Directory – nope, not in any way, shape, or form. In case you decide to use this tutorial for nefarious purposes, we can not be held liable for your stupidity. With that said let’s move on.

If you are trying to recover a local admin password from Windows XP, Vista, 2000, or NT, please refer to last week’s article on how to reset you local admin password.

Using openssl to convert CA certificates to different types

PEM Format

The PEM format is the most common format that Certificate Authorities issue certificates in. PEM certificates usually have extentions such as .pem, .crt, .cer, and .key. They are Base64 encoded ASCII files and contain "-----BEGIN CERTIFICATE-----" and "-----END CERTIFICATE-----" statements. Server certificates, intermediate certificates, and private keys can all be put into the PEM format.


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