Cloudera Engineering Blog

Big Data best practices, how-to's, and internals from Cloudera Engineering and the community

Bayesian Machine Learning on Apache Spark

Markov Chain Monte Carlo methods are another example of useful statistical computation for Big Data that is capably enabled by Apache Spark.

During my internship at Cloudera, I have been working on integrating PyMC with Apache Spark. PyMC is an open source Python package that allows users to easily apply Bayesian machine learning methods to their data, while Spark is a new, general framework for distributed computing on Hadoop. Together, they provide a scalable framework for scalable Markov Chain Monte Carlo (MCMC) methods. In this blog post, I am going to describe my work on distributing large-scale graphical models and MCMC computation.

Markov Chain Monte Carlo Methods

What’s Next for Impala: Focus on Advanced SQL Functionality

Impala 2.0 will add much more complete SQL functionality to what is already the fastest SQL-on-Hadoop solution available.

In September 2013, we provided a roadmap for Impala — the open source MPP SQL query engine for Apache Hadoop, which was on release 1.1 at the time — that documented planned functionality through release 2.0 and beyond.

Improving Query Performance Using Partitioning in Apache Hive

Our thanks to Rakesh Rao of Quaero, for allowing us to re-publish the post below about Quaero’s experiences using partitioning in Apache Hive.

In this post, we will talk about how we can use the partitioning features available in Hive to improve performance of Hive queries.


The New Apache Flume Book is in Early Release

Congratulations to Hari Shreedharan, Cloudera software engineer and Apache Flume committer/PMC member, for the early release of his new O’Reilly Media book, Using Flume: Stream Data into HDFS and HBase. It’s the seventh Hadoop ecosystem book so far that was authored by a current or former Cloudera employee (but who’s counting?).

Why did you decide to write this book?

Big Data Benchmarks: Toward Real-Life Use Cases

The Transaction Processing Council (TPC), working with Cloudera, recently announced the new TPCx-HS benchmark, a good first step toward providing a Big Data benchmark.

In this interview by Roberto Zicari with Francois Raab, the original author of the TPC-C Benchmark, and Yanpei Chen, a Performance Engineer at Cloudera, the interviewees share their thoughts on the next step for benchmarks that reflect real-world use cases.

Running CDH 5 on GlusterFS 3.3

The following post was written by Jay Vyas (@jayunit100) and originally published in the Community.

I have recently spent some time getting Cloudera’s CDH 5 distribution of Apache Hadoop to work on GlusterFS 3.3 using Distributed Replicated 2 Volumes. This is made possible by the fact that Apache Hadoop has a pluggable filesystem architecture that allows the computational components within the CDH 5 distribution to be configured to use alternative filesystems to HDFS. In this case, one can configure CDH 5 to use the Hadoop FileSystem plugin for GlusterFS (glusterfs-hadoop), which allows it to run on GlusterFS 3.3. I’ve provided a diagram below that illustrates the CDH 5 core processes and how they interact with GlusterFS.

How-to: Count Events Like a Data Scientist

The ability to quickly and accurately count complex events is a legitimate business advantage.

In our work as data scientists, we spend most of our time counting things. It is the foundational skill that is used in data cleansing, reporting, feature engineering, and simple-but-effective machine learning models like Naive Bayes classifiers. Hilary Mason has a quote about the benefits of counting that I love:

Apache Hadoop 2.5.0 is Released

The Apache Hadoop community has voted to release Apache Hadoop 2.5.0.

Apache Hadoop 2.5.0 is a minor release in the 2.x release line and includes some major features and improvements, including:

How-to: Use IPython Notebook with Apache Spark

IPython Notebook and Spark’s Python API are a powerful combination for data science.

The developers of Apache Spark have given thoughtful consideration to Python as a language of choice for data analysis. They have developed the PySpark API for working with RDDs in Python, and further support using the powerful IPythonshell instead of the builtin Python REPL.

New in CDH 5.1: HDFS Read Caching

Applications using HDFS, such as Impala, will be able to read data up to 59x faster thanks to this new feature.

Server memory capacity and bandwidth have increased dramatically over the last few years. Beefier servers make in-memory computation quite attractive, since a lot of interesting data sets can fit into cluster memory, and memory is orders of magnitude faster than disk.

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