Is "self sacrifice" worthy?

This is a story of a woman who sacrificed lots of things for her family.

A long long time ago, my husband, our two sons and I had gone out for an ice-cream treat. It was sometime when I was always thinking of curbing unnecessary expenditure. As a selfless person, who was too much in love with her family to deny them of any pleasure, I always chose to sacrifice my own excesses. And it didn’t even feel like a sacrifice ever, because I was a woman of very few needs/ wants/ desires...
So, when my husband asked each one of us to choose our favorite flavor of ice-cream, I responded as usual, “I won’t have any.”

The boys enjoyed one round and ordered another; my response remained the same, “I don’t want any.”

I was happy with my family’s happiness. I was happy that my not indulging in pleasure was perhaps ensuring some more goodies in the future for my dear ones.

But my husband looked at me and said, “Please don’t do this to yourself and to us. I want a happy wife; not a sacrificial lamb. I have seen that too much sacrifice eventually leads to bitterness and victim mentality. And I sure as hell do not want you to develop that. You see, after a period of time, the boys and I will stop asking you for your choice, because we will assume that you don’t want it; we will take you for granted and subconsciously start treating you as a doormat. It will then hurt you and you will feel miserable and unimportant. You will think that we don’t care about you. While in truth we would be behaving naturally, knowing from experience that you don’t care for yourself. That your wishes are not important. So, I suggest that you always take your share and then if you really don’t like it, share it with someone who does. That will be good for all of us. You will learn how to claim your importance in your own and our eyes and we will always ask you. There will be happy all around.”

His talk made sense to me and I couldn’t help but think about many older women who always complained, “I did so much for so and so but today they don’t even think/ care for me.” I also remembered many instances where children would turn back and say, “But why did you do so much? Did we ask for it? You did it because it made you happy. Who asked you to be so self-sacrificing?” This train of thought made me take a re-look at the word 'selfless', equating it with self-sacrifice. That day the meaning of these words opened up for me!

Self-sacrifice is not the balanced way!!!

Hadoop 1.2.1 Installation and Configuration on Single Node

I have experienced difficulties in installing and configuring Hadoop so I want to make one easy guide for installation and configuration of Hadoop 1x. I am assuming that readers have a knowledge of basic Linux commands, hence, I am not going to explain those commands in detail.

I have used Hadoop-1.2.1, jdk-7, and Ubuntu(Linux) in our setup.

Install SSH:

• We require SSH for remote login to different machines for Map Reduce task to run on Hadoop cluster

Commands:

• sudo apt-get update
  
  • updates list of packages
   
• sudo apt-get install openssh-server
  • Installs OpenSSH Server
  
  
   
  
  
  

Generate Keys:

• Hadoop logged in to remote machines many times while running a MapReduce task. Therefore, we need to make a passwordless entry for Hadoop to all the nodes in our cluster.

Commands:

• ssh CSE-DBMS-04
  
  • instead of CSE-DBMS-04, you should write your system's hostname or localhost. It asks for a password
  
  
  
  
  
  
  
• ssh-keygen
  • generates SSH Keys
  
• ENTER FILE NAME:
  • no need to write anything simply press enter as we want to use default settings
• ENTER PASSPHRASE:
  • no need to write anything simply press enter as we want to use default settings
• cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys
  
  • Copy id_rsa.pub key to authorized keys to make a passwordless entry for the user
• ssh CSE-DBMS-04
  
  • Now it should not ask for a password
  
  
  

Install Java

• I prefer offline Java installation. So I have already downloaded Java tarball and place it in my Downloads directory

Commands:

• sudo mkdir -p /usr/lib/jvm/
  • create a directory for Java
  
  
  
• sudo tar -xvf ~/Downloads/jdk-7u67-linux-x64.tar.gz -C /usr/lib/jvm
  • extract and copy the content of Java tarball to Java directory
  
  
  
  
• cd /usr/lib/jvm
  • go to Java directory
  
  
  
• sudo ln -s jdk1.7.0_67 java-1.7.0-sun-amd64
  • generate a symbolic link to jdk directory which will be used in Hadoop configuration
  
  
  
  
• sudo update-alternatives --config java
  • checking and setting Java alternatives
  
  
  
• sudo nano $HOME/.bashrc
  • setting the Java path. Add following two lines at the end of this file
    • export JAVA_HOME="/usr/lib/jvm/jdk1.7.0_67"
    • export PATH="$PATH:$JAVA_HOME/bin"
    
    
    
    
    
    
• exec bash
  • restarts bash(terminal)
  
  
  
• java
  • it should not show "command not found!" error
  
  
  
  

Install Hadoop:

• First, we need to download the required tarball of Hadoop.

Commands:

• sudo mkdir -p /usr/local/hadoop/
  • create Hadoop directory
  
  
  
• cd ~/Downloads
• sudo tar -xvf ~/Downloads/hadoop-1.2.1-bin.tar.gz
• sudo cp -r hadoop-1.2.1/* /usr/local/hadoop/
  • extract and copy Hadoop files from tarball to the Hadoop directory
  
  
  
  
  
  
  
•  sudo nano $HOME/.bashrc
  • setting the Hadoop path. Add following lines at the end of this file
    • export HADOOP_PREFIX=/usr/local/hadoop
    • export PATH=$PATH:$HADOOP_PREFIX/bin
    
    
    
    
• exec bash
  • restarts bash(terminal)
  
  
  
• hadoop
  • it should not show "command not found!" error
  
  
  

Configuration of Hadoop

• We are setting some environment variables and changing some configuration file according to our cluster setup.

Commands:

• cd /usr/local/hadoop/conf
  • go to configuration directory of Hadoop
  
  
  
• sudo nano hadoop-env.sh
  • open environment variable file and add following two lines at its respective place in file. They are already available in a file with some different values so keep it as it is and add this lines after it respectively
    • export JAVA_HOME=/usr/lib/jvm/java-1.7.0-sun-amd64
    • export HADOOP_OPTS=-Djava.net.preferIPv4Stack=true
    
    
    
    
    
• sudo nano core-site.xml
  • open HDFS configuration file and set name server address and tmp dir value as shown in below figure. you have to use your hostname instead of "CSE-DBMS-04" 
  • fs.default.name   hdfs://CSE-DBMS-04:10001
  • hadoop.tmp.dir   /usr/local/hadoop/tmp
  
  
  
  
  
• sudo nano mapred-site.xml
  • Open Map Reduce configuration file and set job tracker value. you have to write your hostname instead of "CSE-DBMS-04"
  • mapred.job.tracker   CSE-DBMS-04:10002
  
  
  
  
  
• sudo mkdir /usr/local/hadoop/tmp
  • create tmp directory to store all files on the data node
  
  
  
  
• sudo chown hadoop /usr/local/hadoop/tmp
  • change owner of the directory to avoid access control issues. write your username instead of "hadoop"
  
  
  
• sudo chown hadoop /usr/local/hadoop
  • change owner of the directory to avoid access control issues. write your username instead of "hadoop"
  
  
  
  

Format DFS (skip this step if you are going for Multi-Node setup):

• Now we are ready to format our Distributed File System (DFS)

Command:

• hadoop namenode -format
  • Check for the message "namenode successfully formatted"
  
  
  

Start all process:

• We are ready to start our hadoop cluster (though only single node)

Commands:

• start-all.sh
  • to start all (name-node, secondary name node, data node, job tracker, task tracker)
  
  
  
• jps
  • to check whether all services (i.e. name node, secondary name node, data node, job tracker, task tracker) started or not
  
  
  

To check cluster details on web interface:

• Open any browser and got following address:
  • http://CSE-DBMS-04:50070/dfshealth.jsp
    • for DFS (name-node) details. Write your hostname instead of "CSE-DBMS-04"
    
    
    
  • http://CSE-DBMS-04:50030/jobtracker.jsp
    • for Map Reduce (job tracker) details. Write your hostname instead of "CSE-DBMS-04"
    
    
    

Stop all processes:

• If you want to stop (shut down) all your Hadoop cluster services

Command:

• stop-all.sh

For any queries you can write in a comment or mail me at "brijeshbmehta@gmail.com"

Courtesy: Mr. Anand Kumar, NIT, Trichy

Originally posted on 14/12/2016 at https://brijeshbmehta.wordpress.com/2016/12/14/hadoop-1x-installation-and-configuration-on-single-node/