Hadoop Beginner's Guide

Time for action – getting web server data into Hadoop

Let's take a look at how we can simplistically copy data from a web server onto HDFS.

1. Retrieve the text of the NameNode web interface to a local file:

   $ curl localhost:50070 > web.txt
   

2. Check the file size:

   $ ls -ldh web.txt 
   

   You will receive the following response:

   -rw-r--r-- 1 hadoop hadoop 246 Aug 19 08:53 web.txt
   

3. Copy the file to HDFS:

   $ hadoop fs -put web.txt web.txt
   

4. Check the file on HDFS:

   $ hadoop fs -ls 
   

   You will receive the following response:

   Found 1 items
   -rw-r--r--   1 hadoop supergroup        246 2012-08-19 08:53 /user/hadoop/web.txt
   

What just happened?

There shouldn't be anything that is surprising here. We use the curl utility to retrieve a web page from the embedded web server hosting ...