Layer4

Testing BigData projects

Posted by in Data, Java

Writing tests that use a traditional database is hard. But writing tests in a project using Hadoop is really harder. Hadoop stacks are complex pieces of software and if you want to test your Hadoop projects, it may be a real nightmare: – many components are involved, you are not just using HBase, but HBase, Zookeeper and a DFS. – a lot of configuration is needed – cleaning the data of the previous tests relies on many steps: truncate the HBase table, stop and delete the running Oozie workflows, clean…read more

Solr: manage time-based collections

Posted by in Data

If you use Solr as your fulltext search engine, you may be frustated to miss the excellent tool Curator from Elastic, which allow you to manage your indices. Cloudera offers an admin tool for Solr, named solrctl, a light utility to supervise a SolrCloud deployment. Although solrctl has some useful commands, you don’t have the possibility to delete old time-based collections. Time-based collections, and globally shard/partition per time frame, is a common pattern for agregation but also for many other use cases. The idea is simple, the collections have names…read more

HBase: having fun with the shell

Posted by in Data

HBase shell is a full interactive JRuby shell (IRB) providing tools allowing you to query your data or execute admin commands on a HBase cluster. Since it uses JRuby, this shell is a powerful interactive scripting environment. This post is not about presenting you the commands available in the shell, you can easily find documentation or article on the Internet, but more about the possibilities of the shell. Add custom command Actually, there is not easy way to extend the set of available commands in HBase shell. If you want…read more

Knox in production: avoid pitfalls and common mistakes

Posted by in Data, Java

I’ve already post articles about Knox some weeks ago about two subjects: how to use the HBase REST API througth Knox and how to submit Spark job via the Knox API. In my current mission, many projects are now using Knox as main gateway for many services like HBase and HDFS, but also for Oozie, Yarn… After some weeks of development and deployment in production, I’ve decided to write a post about some troubles that you may encouter when you are using the Java client. NOTE I’m a great supporter…read more

Working with Parquet files

Posted by in Data

Apache Parquet is a columnar storage format available for most of the data processing frameworks in the Hadoop ecosystem: Hive Pig Spark Drill Arrow Apache Impala Cascading Crunch Tajo … and many more! In Parquet, the data are compressed column by column. This means that commands like these: hdfs dfs -cat hdfs://nn1.example.com/file1 hdfs dfs -text /…/file2 can not work anymore on Parquet files, all you can see are binary chunks on your terminal. Thankfully, Parquet provides an useful project in order to inspect Parquet file: Parquet Tools For a more…read more

Using HBase REST API with the Knox Java client

Posted by in Data

I’ve already introduced Knox in a previous post in order to deploy Spark Job with Knox using the Java client. This post is still about the Knox Java client, but we’ll see here an other usage with HBase. HBase provides a well documented and rich REST API with many endpoints exposing the data in various formats (JSON, XML and Protobuf!). First, we need to import the dependencies for the Knox Java client: <dependency> <groupId>org.apache.knox</groupId> <artifactId>gateway-shell</artifactId> <version>0.10.0</version> </dependency> Then, let’s write some code: Hadoop session = Hadoop.login(“https://$KNOX_SERVER:8443/gateway/default”, “user”, “password”); String tableName…read more

Submitting Spark Job via Knox on Yarn

Posted by in Data

Apache Knox is a REST API Gateway for interacting with Apache Hadoop clusters. It offers an extensible reverse proxy exposing securely REST APIs and HTTP based services in any Hadoop platform. Althought Knox is not designed to be a channel for high volume data ingest or export, it is perfectly suited for exposing a single entrypoint to your cluster and can be seen as a bastion for all your applications. One of the possible use-case of Knox is to deploy applications on Yarn, like Spark or Hive, without exposing the…read more

High performance RSS/Atom parsing

Posted by in Data, Java

Parsing RSS feeds is very easy in Java. Several libs exist to get the job done: feed4j, rssowl, Apache Abdera and many others. But the most commly used is ROME. ROME is a set of RSS and Atom Utilities for Java. It makes it easy to work in Java with most syndication formats: RSS 0.9x, 1.0, 2.0 and Atom 0.3, 1.0. Reading RSS from a source is dead-simple, you need these dependencies: <!– Rome Atom+RSS –> <dependency> <groupId>net.java.dev.rome</groupId> <artifactId>rome</artifactId> <version>1.0.0</version> </dependency> <dependency> <groupId>net.java.dev.rome</groupId> <artifactId>rome-fetcher</artifactId> <version>1.0.0</version> </dependency> and a piece of…read more

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Myrrix, the REST-ified Mahout for real-time recommandations

Posted by in Data

Myrrix is a complete, real-time, scalable clustering and recommender system, evolved from Apache Mahout. The full Myrrix system uses two components: a Computation Layer and one or many Serving Layers. While the Computation Layer computes the large machine learning models needed by the Serving Layer, the Serving Layer is a Java HTTP server application. This server serves user requests in real-time, making recommendations and receiving new input via a REST API. Many instances of the Serving Layer may be run for horizontal scalability. In stand-alone mode, one Serving Layer instance…read more

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