title: Anomaly detection using mapreduce
body: <p>I'm new to Apache Hadoop and i'm really looking forward to explore more features of it. After the basic wordcount example i wanted to up the ante a little bit. So i sat down with this problem statement which i got by going through Hadoop In Action book.
  "Take a web server log file . Write a MapReduce program to
  aggregate the number of visits for each IP address. Write another MapReduce
  program to find the top K IP addresses in terms of visits. These frequent
  visitors may be legitimate ISP proxies (shared among many users) or they
  may be scrapers and fraudsters (if the server log is from an ad network)."
  Can anybody help me out as to how i should start ? Its kind of tough to actually write our own code since hadoop only gives wordcount as a basic example to kick start .
  Any help gratefully appreciated . Thanks.</p>