Cloudera Engineering Blog · Hadoop Posts
In this multipart series, fully explore the tangled ball of thread that is YARN.
YARN (Yet Another Resource Negotiator) is the resource management layer for the Apache Hadoop ecosystem. YARN has been available for several releases, but many users still have fundamental questions about what YARN is, what it’s for, and how it works. This new series of blog posts is designed with the following goals in mind:
Learn about the new functionality coming aboard Cloudera Navigator, the trail-blazing solution for metadata management and lineage in Apache Hadoop.
More than two years ago, Cloudera introduced Cloudera Navigator 1.0, which was the first offering to unify auditing across enterprise Apache Hadoop deployments. About a year later, Cloudera released Cloudera Navigator 2.0, which introduced another first for Hadoop: comprehensive metadata management and lineage to Hadoop. Today, more than 200 customers across numerous industries use Cloudera Navigator in production to deliver trust and visibility to their Hadoop deployments.
The Strata + Hadoop World NYC 2015 (Sept. 29-Oct. 3) agenda was published in the last few days. Congratulations to all accepted presenters!
In this post, I just want to provide a concise digest of the tutorials and sessions that will involve Cloudera or Intel engineers and/or interesting use cases. There are many worthy sessions from which to choose, so we hope this list will influence your decisions about where to spend your time during the week! (Note that evening meetups are a work in progress; more on those later.)
Evaluating which streaming architectural pattern is the best match to your use case is a precondition for a successful production deployment.
The Apache Hadoop ecosystem has become a preferred platform for enterprises seeking to process and understand large-scale data in real time. Technologies like Apache Kafka, Apache Flume, Apache Spark, Apache Storm, and Apache Samza are increasingly pushing the envelope on what is possible. It is often tempting to bucket large-scale streaming use cases together but in reality they tend to break down into a few different architectural patterns, with different components of the ecosystem better suited for different problems.
Learn how to read FIX message files directly with Hive, create a view to simplify user queries, and use a flattened Apache Parquet table to enable fast user queries with Impala.
The Financial Information eXchange (FIX) protocol is used widely by the financial services industry to communicate various trading-related activities. Each FIX message is a record that represents an action by a financial party, such as a new order or an execution report. As the raw point of truth for much of the trading activity of a financial firm, it makes sense that FIX messages are an obvious data source for analytics and reporting in Apache Hadoop.
This new feature gives Hadoop admins the commonplace ability to replace failed DataNode drives without unscheduled downtime.
Hot swapping—the process of replacing system components without shutting down the system—is a common and important operation in modern, production-ready systems. Because disk failures are common in data centers, the ability to hot-swap hard drives is a supported feature in hardware and server operating systems such as Linux and Windows Server, and sysadmins routinely upgrade servers or replace a faulty components without interrupting business-critical services.
Apache Hadoop ecosystem, time to celebrate! The much-anticipated, significantly updated 4th edition of Tom White’s classic O’Reilly Media book, Hadoop: The Definitive Guide, is now available.
The Hadoop ecosystem has changed a lot since the 3rd edition. How are those changes reflected in the new edition?
Thanks to Big Data Solutions Architect Matthieu Lieber for allowing us to republish the post below.
A customer of mine wants to take advantage of both worlds: work with his existing Apache Avro data, with all of the advantages that it confers, but take advantage of the predicate push-down features that Parquet provides. How to reconcile the two?
Having a good grasp of HDFS recovery processes is important when running or moving toward production-ready Apache Hadoop. In the conclusion to this two-part post, pipeline recovery is explained.
An important design requirement of HDFS is to ensure continuous and correct operations that support production deployments. For that reason, it’s important for operators to understand how HDFS recovery processes work. In Part 1 of this post, we looked at lease recovery and block recovery. Now, in Part 2, we explore pipeline recovery.
Having a good grasp of HDFS recovery processes is important when running or moving toward production-ready Apache Hadoop.
An important design requirement of HDFS is to ensure continuous and correct operations to support production deployments. One particularly complex area is ensuring correctness of writes to HDFS in the presence of network and node failures, where the lease recovery, block recovery, and pipeline recovery processes come into play. Understanding when and why these recovery processes are called, along with what they do, can help users as well as developers understand the machinations of their HDFS cluster.
Thanks to Călin-Andrei Burloiu, Big Data Engineer at antivirus company Avira, and Radu Pastia, Senior Software Developer in the Big Data Team at Orange, for the guest post below about the Couchdoop connector for bringing Couchbase data into Hadoop.
Couchdoop is a Couchbase connector for Apache Hadoop, developed by Avira on CDH, that allows for easy, parallel data transfer between Couchbase and Hadoop storage engines. It includes a command-line tool, for simple tasks and prototyping, as well as a MapReduce library, for those who want to use Couchdoop directly in MapReduce jobs. Couchdoop works natively with CDH 5.x.
Couchdoop can help you:
You may have noticed that this report went on hiatus for December 2014 due to a lack of critical news mass (plus, we realize that most of you are out of the loop until mid-January). It’s back with a vengeance, though:
Strata + Hadoop World San Jose 2015 (Feb. 17-20) is a focal point for learning about production-izing Hadoop.
Strata + Hadoop World sessions have always been indispensable for learning about Hadoop internals, use cases, and admin best practices. When deep learning is needed, however—and deep dives are a necessity if you’re running Hadoop in production, or aspire to—tutorials are your ticket.
Learn how to set up a Hadoop cluster in a way that maximizes successful production-ization of Hadoop and minimizes ongoing, long-term adjustments.
Previously, we published some recommendations on selecting new hardware for Apache Hadoop deployments. That post covered some important ideas regarding cluster planning and deployment such as workload profiling and general recommendations for CPU, disk, and memory allocations. In this post, we’ll provide some best practices and guidelines for the next part of the implementation process: configuring the machines once they arrive. Between the two posts, you’ll have a great head start toward production-izing Hadoop.
A new Spark tutorial and Trifacta deployment option make Cloudera Live even more useful for getting started with Apache Hadoop.
When it comes to learning Hadoop and CDH (Cloudera’s open source platform including Hadoop), there is no better place to start than Cloudera Live (cloudera.com/live). With a quick, one-button deployment option, Cloudera Live launches a four-node Cloudera cluster that you can learn and experiment in free for two-weeks. To help plan and extend the capabilities of your cluster, we also offer various partner deployments. Building on the addition of interactive tutorials and Tableau and Zoomdata integration, we have added a new tutorial on Apache Spark and a new Trifacta partner deployment.
Support for transparent, end-to-end encryption in HDFS is now available and production-ready (and shipping inside CDH 5.3 and later). Here’s how it works.
Apache Hadoop 2.6 adds support for transparent encryption to HDFS. Once configured, data read from and written to specified HDFS directories will be transparently encrypted and decrypted, without requiring any changes to user application code. This encryption is also end-to-end, meaning that data can only be encrypted and decrypted by the client. HDFS itself never handles unencrypted data or data encryption keys. All these characteristics improve security, and HDFS encryption can be an important part of an organization-wide data protection story.
Our “Top 10″ list of blog posts published during a calendar year is a crowd favorite (see the 2013 version here), in particular because it serves as informal, crowdsourced research about popular interests. Page views don’t lie (although skew for publishing date—clearly, posts that publish earlier in the year have pole position—has to be taken into account).
In 2014, a strong interest in various new components that bring real time or near-real time capabilities to the Apache Hadoop ecosystem is apparent. And we’re particularly proud that the most popular post was authored by a non-employee.
- How-to: Create a Simple Hadoop Cluster with VirtualBox
by Christian Javet
Explains how t set up a CDH-based Hadoop cluster in less than an hour using VirtualBox and Cloudera Manager.
- Why Apache Spark is a Crossover Hit for Data Scientists
by Sean Owen
An explanation of why Spark is a compelling multi-purpose platform for use cases that span investigative, as well as operational, analytics.
- How-to: Run a Simple Spark App in CDH 5
by Sandy Ryza
Helps you get started with Spark using a simple example.
- New SQL Choices in the Apache Hadoop Ecosystem: Why Impala Continues to Lead
by Justin Erickson, Marcel Kornacker & Dileep Kumar
Open benchmark testing of Impala 1.3 demonstrates performance leadership compared to alternatives (by 950% or more), while providing greater query throughput and with a far smaller CPU footprint.
- Apache Kafka for Beginners
by Gwen Shapira & Jeff Holoman
When used in the right way and for the right use case, Kafka has unique attributes that make it a highly attractive option for data integration.
- Apache Hadoop YARN: Avoiding 6 Time-Consuming “Gotchas”
by Jeff Bean
Understanding some key differences between MR1 and MR2/YARN will make your migration much easier.
- Impala Performance Update: Now Reaching DBMS-Class Speed
by Justin Erickson, Greg Rahn, Marcel Kornacker & Yanpei Chen
As of release 1.1.1, Impala’s speed beat the fastest SQL-on-Hadoop alternatives–including a popular analytic DBMS running on its own proprietary data store.
- The Truth About MapReduce Performance on SSDs
by Karthik Kambatla & Yanpei Chen
It turns out that cost-per-performance, not cost-per-capacity, is the better metric for evaluating the true value of SSDs. (See the session on this topic at Strata+Hadoop World San Jose in Feb. 2015!)
- How-to: Translate from MapReduce to Spark
by Sean Owen
The key to getting the most out of Spark is to understand the differences between its RDD API and the original Mapper and Reducer API.
- How-to: Write and Run Apache Giraph Jobs on Hadoop
by Mirko Kämpf
Explains how to create a test environment for writing and testing Giraph jobs, or just for playing around with Giraph and small sample datasets.
Benchmarking Big Data systems is nontrivial. Avoid these traps!
Here at Cloudera, we know how hard it is to get reliable performance benchmarking results. Benchmarking matters because one of the defining characteristics of Big Data systems is the ability to process large datasets faster. “How large” and “how fast” drive technology choices, purchasing decisions, and cluster operations. Even with the best intentions, performance benchmarking is fraught with pitfalls—easy to get numbers, hard to tell if they are sound.
A significant vulnerability affecting the entire Apache Hadoop ecosystem has now been patched. What was involved?
By now, you may have heard about the POODLE (Padding Oracle On Downgraded Legacy Encryption) attack on TLS (Transport Layer Security). This attack combines a cryptographic flaw in the obsolete SSLv3 protocol with the ability of an attacker to downgrade TLS connections to use that protocol. The result is that an active attacker on the same network as the victim can potentially decrypt parts of an otherwise encrypted channel. The only immediately workable fix has been to disable the SSLv3 protocol entirely.
The Apache Hadoop community has voted to release Hadoop 2.6. Congrats to all contributors!
This new release contains a variety of improvements, particularly in the storage layer and in YARN. We’re particularly excited about the encryption-at-rest feature in HDFS!
Cloudera’s culture is premised on innovation and teamwork, and there’s no better example of them in action than our internal hackathon.
Cloudera Engineering doubled-down on its “hackathon” tradition last week, with this year’s edition taking an around-the-clock approach thanks to the HQ building upgrade since the 2013 edition (just look at all that space!).
The number of powerful data query tools in the Apache Hadoop ecosystem can be confusing, but understanding a few simple things about your needs usually makes the choice easy.
Ah, the good old days. I recall vividly that in 2007, I was faced to store 1 billion XML documents and make them accessible as well as searchable. I had few choices on a given shoestring budget: build something one my own (it was the rage back then—and still is), use an existing open source database like PostgreSQL or MySQL, or try this thing that Google built successfully and that was now implemented in open source under the Apache umbrella: Hadoop.
The combination of OpenShift and Kite SDK turns out to be an effective one for developing and testing Apache Hadoop applications.
At Cloudera, our engineers develop a variety of applications on top of Hadoop to solve our own data needs (here and here). More recently, we’ve started to look at streamlining our development process by using a PaaS (Platform-as-a-Service) for some of these applications. Having single-click deployment and updates to consistent development environments lets us onboard new developers more quickly, and helps ensure that code is written and tested along patterns that will ensure high quality.
Cloudera Enterprise 5.2 contains new functionality for security, cloud deployments, and real-time architectures, and support for the latest open source component releases and partner technologies.
We’re pleased to announce the release of Cloudera Enterprise 5.2 (comprising CDH 5.2, Cloudera Manager 5.2, Cloudera Director 1.0, and Cloudera Navigator 2.1).
Thanks to M. Asokan, Chief Architect at Syncsort, for the guest post below.
Apache Sqoop provides a framework to move data between HDFS and relational databases in a parallel fashion using Hadoop’s MR framework. As Hadoop becomes more popular in enterprises, there is a growing need to move data from non-relational sources like mainframe datasets to Hadoop. Following are possible reasons for this:
Using this new tutorial alongside Cloudera Live is now the fastest, easiest, and most hands-on way to get started with Hadoop.
At Cloudera, developer enablement is one of our most important objectives. One only has to look at examples from history (Java or SQL, for example) to know that knowledge fuels the ecosystem. That objective is what drives initiatives such as our community forums, the Cloudera QuickStart VM, and this blog itself.
With 1.4, Impala’s performance lead over the SQL-on-Hadoop ecosystem gets wider, especially under multi-user load.
As noted in our recent post about the Impala 2.x roadmap (“What’s Next for Impala: Focus on Advanced SQL Functionality”), Impala’s ecosystem momentum continues to accelerate, with nearly 1 million downloads since the GA of 1.0, deployment by most of Cloudera’s enterprise data hub customers, and adoption by MapR, Amazon, and Oracle as a shipping product. Furthermore, in the past few months, independent sources such as IBM Research have confirmed that “Impala’s database-like architecture provides significant performance gains, compared to Hive’s MapReduce- or Tez-based runtime.”
The meetup opportunities during the conference week are more expansive than ever — spanning Impala, Spark, HBase, Kafka, and more.
Strata + Hadoop World 2014 is a kaleidoscope of experiences for attendees, and those experiences aren’t contained within the conference center’s walls. For example, the meetups that occur during the conf week (which is concurrent with NYC DataWeek) are a virtual track for developers — and with Strata + Hadoop World being bigger than ever, so is the scope of that track.
What does a “Big Data engineer” do, and what does “Big Data architecture” look like? In this post, you’ll get answers to both questions.
Apache Hadoop has come a long way in its relatively short lifespan. From its beginnings as a reliable storage pool with integrated batch processing using the scalable, parallelizable (though inherently sequential) MapReduce framework, we have witnessed the recent additions of real-time (interactive) components like Impala for interactive SQL queries and integration with Apache Solr as a search engine for free-form text exploration.
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.
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.
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:
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.
Cloudera Community forums are proving their value as an important contributor to a rich user experience.
It’s been almost exactly one year since the debut of the Cloudera Community forums. In addition to doing the birthday shout-out, I thought it would be interesting to bring you up to date about adoption and usage patterns.
With this new release, setting up a separate MIT KDC for cluster authentication services is no longer necessary.
Kerberos (initially developed by MIT in the 1980s) has been adopted by every major component of the Apache Hadoop ecosystem. Consequently, Kerberos has become an integral part of the security infrastructure for the enterprise data hub (EDH).
Cloudera Enterprise’s newest release contains important new security and performance features, and offers support for the latest innovations in the open source platform.
We’re pleased to announce the release of Cloudera Enterprise 5.1 (comprising CDH 5.1, Cloudera Manager 5.1, and Cloudera Navigator 2.0).
It was good to see Jay Kreps (@jaykreps), the LinkedIn engineer who is the tech lead for that company’s online data infrastructure, visit Cloudera Engineering yesterday to spread the good word about Apache Kafka.
Kafka, of course, was originally developed inside LinkedIn and entered the Apache Incubator in 2011. Today, it is being widely adopted as a pub/sub framework that works at massive scale (and which is commonly used to write to Apache Hadoop clusters, and even data warehouses).
There’s an important new addition coming to the Apache Hadoop book ecosystem. It’s now in early release!
We are very happy to announce that the new Apache Hadoop book we have been writing for O’Reilly Media, Hadoop Application Architectures, is now available as an early release! It contains the first two chapters and can be found in O’Reilly’s Catalog and via Safari.
Pretty busy for early Summer:
Google’s Jeff Dean — among the original architects of MapReduce, Bigtable, and Spanner — revealed some fascinating facts about Google’s internal environment at Cloudera HQ recently.
Earlier this week, we were pleased to welcome Google Senior Fellow Jeff Dean to Cloudera’s Palo Alto HQ to give an overview of some of his group’s current research. Jeff has a peerless pedigree in distributed computing circles, having been deeply involved in the design and implementation of Google’s original advertising serving system, MapReduce, Bigtable, Spanner, and a host of other projects.
Find Cloudera tech talks in Texas, Oregon, Washington DC, Illinois, Georgia, Japan, and across the SF Bay Area during the next calendar quarter.
Below please find our regularly scheduled quarterly update about where to find tech talks by Cloudera employees – this time, for the third calendar quarter of 2014 (July through September; traditionally, the least active quarter of the year). Note that this list will be continually curated during the period; complete logistical information may not be available yet. And remember, many of these talks are in “free” venues (no cost of entry).
Prefer IntelliJ IDEA over Eclipse? We’ve got you covered: learn how to get ready to contribute to Apache Hadoop via an IntelliJ project.
It’s generally useful to have an IDE at your disposal when you’re developing and debugging code. When I first started working on HDFS, I used Eclipse, but I’ve recently switched to JetBrains’ IntelliJ IDEA (specifically, version 13.1 Community Edition).
More good news!
Using an appropriate network representation and the right tool set are the key factors in successfully merging structured and time-series data for analysis.
In Part 1 of this series, you took your first steps for using Apache Giraph, the highly scalable graph-processing system, alongside Apache Hadoop. In this installment, you’ll explore a general use case for analyzing time-dependent, Big Data graphs using data from multiple sources. You’ll learn how to generate random large graphs and small-world networks using Giraph – as well as play with several parameters to probe the limits of your cluster.
In its relatively short lifetime (co-founded by Twitter and Cloudera in July 2013), Parquet has already become the de facto standard for columnar storage of Apache Hadoop data — with native support in Impala, Apache Hive, Apache Pig, Apache Spark, MapReduce, Apache Tajo, Apache Drill, Apache Crunch, and Cascading (and forthcoming in Presto and Shark). Parquet adoption is also broad-based, with employees of the following companies (partial list) actively contributing:
Learn how to convert your data to the Parquet columnar format to get big performance gains.
Using a columnar storage format for your data offers significant performance advantages for a large subset of real-world queries. (Click here for a great introduction.)
Thanks to recent work upstream, YARN is now a highly available service. This post explains its architecture and configuration details.
YARN, the next-generation compute and resource management framework in Apache Hadoop, until recently had a single point of failure: the ResourceManager, which coordinates work in a YARN cluster. With planned (upgrades) or unplanned (node crashes) events, this central service, and YARN itself, could become unavailable.
Understanding some key differences between MR1 and MR2/YARN will make your migration much easier.
Here at Cloudera, we recently finished a push to get Cloudera Enterprise 5 (containing CDH 5.0.0 + Cloudera Manager 5.0.0) out the door along with more than 100 partner certifications.
The community has voted to release Apache Hadoop 2.4.0.
Hadoop 2.4.0 includes myriad improvements to HDFS and MapReduce, including (but not limited to):
More good news for the ecosystem!