Distributed Systems
Consistent Hash Ring
Consistent hashing is a special kind of hashing such that when a hash table is resized and consistent hashing is used, only K/n keys need to be remapped on average, where K is the number of keys, and n is the number of slots. In contrast, in most traditional hash tables, a change in the number of array slots causes nearly all keys to be remapped. Consistent hashing achieves the same goals as Rendezvous hashing (also called HRW Hashing). The two techniques use different algorithms and were devised independently and contemporaneously.
Getting Started with Hadoop 2.0
Apache™ Hadoop® is an open source software project that enables the distributed processing of large data sets across clusters of commodity servers. It is designed to scale up from a single server to thousands of machines, with a very high degree of fault tolerance. Rather than relying on high-end hardware, the resiliency of these clusters comes from the software’s ability to detect and handle failures at the application layer. Hadoop 1 popularized MapReduce programming for batch jobs and demonstrated the potential value of large scale, distributed processing. MapReduce, as implemented in Hadoop 1, can be I/O intensive, not suitable for interactive analysis, and constrained in support for graph, machine learning and on other memory intensive algorithms. Hadoop developers rewrote major components of the file system to produce Hadoop 2. To get started with the new version, it helps to understand the major differences between Hadoop 1 and 2.
Running Hadoop 1.1.2 on Ubuntu Linux (Single-Node Cluster)
In this tutorial I will describe the required steps for setting up a pseudo-distributed, single-node Hadoop cluster backed by the Hadoop Distributed File System, running on Ubuntu Linux. This tutorial has been tested with the following software versions: Ubuntu 13.04 Apache Hadoop 1.1.2 (Released on February 15th, 2013) Prerequisites Oracle Java 7 Hadoop requires a working Java 1.5+ (aka Java 5) installation. In this tutorial, I will describe the installation of Java 1.7.0 Update 21.