Introduction to Apache Spark

1. A PA C H E S PA R K S TA M P E D E C O N 2 0 1 4 S T E V E N B O R R E L L I @stevendborrelli A S T E R I S
2. A B O U T M E F O U N D E R , A S T E R I S ( J A N 2 0 1 4 ) O R G A N I Z E R O F S T L M A C H I N E L E A R N I N G A N D D O C K E R S T L S Y S T E M S E N G I N E E R I N G , H P C , B I G D A TA & C L O U D N E X T G E N E R AT I O N I N F R A S T R U C T U R E F O R D E V E L O P E R S
3. S PA R K I N F I V E S E C O N D S is a replacement for
4. WHY DO WE NEED TO REPLACE MAPREDUCE?
5. M A P R E D U C E I S A W E S O M E ! Allows us to process enormous amounts of data in parallel
6. M A P R E D U C E M A P R E D U C E : S I M P L I F I E D D ATA P R O C E S S I N G O N L A R G E C L U S T E R S ( 2 0 0 4 ) 
 J E F F R E Y D E A N A N D S A N J AY G H E M AWAT
7. HITTING THE LIMITS OF HADOOP’s MAPREDUCE
8. T H E P R O B L E M S W I T H M A P R E D U C E ! API: Low-Level & Complex
9. M A P R E D U C E I S S U E S ! • Latency • Execution time impacted by “stragglers” • Lack of in-memory caching • Intermediate steps persisted to disk • No shared state
10. T H E P R O B L E M S W I T H M A P R E D U C E ! Not optimal for: M A C H I N E L E A R N I N G G R A P H S S T R E A M P R O C E S S I N G
11. I M P R O V I N G M A P R E D U C E A PA C H E T E Z
12. ! • Generalize to different workloads • Sub-Second Latency • Scalable and Fault Tolerant • Easy to use API N E X T M A P R E D U C E : G O A L S
13. T O P S PA R K F E AT U R E S • Fast, fault-tolerant in-memory data structures (RDD) • Compatibility with Hadoop ecosystem • Rich, easy-to-use API supports Machine Learning, Graphs and Streaming • Interactive Shell

14. S PA R K S TA C K
15. R E S I L I E N T D I S T R I B U T E D D ATA S E T • Immutable in-memory collections • Fast recovery on failure • Control caching and persistence to memory/disk • Can partition to avoid shuffles
16. R D D L I N E A G E lines = spark.textFile(“hdfs://errors/...”) errors = lines.filter(_.startsWith(“ERROR”)) messages = errors.map(_.split(‘\t’)(2))
17. L A N G U A G E S U P P O R T • Spark is written in • Uses Scala collections & Akka Actors • Java, Python native support (Python support can lag), lambda support in Java8/Spark 1.0 • R Bindings through SparkR • Functional programming paradigm
18. R D D T R A N S F O R M AT I O N S Transformations create a new RDD map filter flatMap sample union distinct groupByKey reduceByKey sortByKey join cogroup cartesian Transformations are evaluated lazily.
19. R D D A C T I O N S Actions Return a value reduce collect count countByKey countByValue countApprox ! foreach saveAsSequenceFile saveAsTextFile first take(n) takeSample toArray Invoking an Action will cause all previous Transformations to be evaluated.
20. TA S K S C H E D U L E R H T T P : / / A M P C A M P. B E R K E L E Y. E D U / W P - C O N T E N T / U P L O A D S / 2 0 1 2 / 0 6 / M AT E I - Z A H A R I A - PA R T- 1 - A M P - C A M P - 2 0 1 2 - S PA R K - I N T R O . P D F • Runs general task graphs ! • Pipelines functions where possible
 • Cache-aware data reuse & locality ! • Partitioning- aware to avoid shuffles
21. SPARK ECOSYSTEM
22. S PA R K S TA C K Integrated platform for disparate workloads
23. S PA R K S T R E A M I N G • Micro-Batch: Discretized Stream (DStream) • ~1 sec latency • Fault tolerant • Shares Much of the same code as Batch
24. T O P 1 0 H A S H TA G S I N L A S T 1 0 M I N // Create the stream of tweets val tweets = ssc.twitterStream(<username>, <password>) // Count the tags over a 10 minute window val tagCounts = tweets.flatMap(statuts => getTags(status)) .countByValueAndWindow(Minutes(10), Second(1)) // Sort the tags by counts val sortedTags = tagCounts.map { case (tag, count) => (count, tag) } (_.sortByKey(false)) // Show the top 10 tags sortedTags.foreach(showTopTags(10) _)
26. • 10x + speedup after data is cached • In-memory materialized views • Supports HiveQL, UDFs, etc. • New Catalyst SQL engine coming in 1.0 includes SchemaRDD to mix & match RDD/SQL in code.
27. • Implementation of PowerGraph, Pregel on Spark • .5x the speed of GraphLab, but more fault-tolerant
28. • Machine Learning library, part of Spark core. • Uses jblas & gfortran. Python supports NumPy. • Growing number of algorithms: 
 SVM, ALS, Naive Bayes, K-Means, Linear & Logistic Regression. (SVD/PCA, CART, L-BGFS coming in 1.x) M L L I B
29. • MLI: Higher level library to support Tables (dataframes), Linear Algebra, Optimizers. • MLI: alpha software, limited activity • Can use Scikit-Learn or SparkR to run models on Spark. M L L I B +
30. MOMENTUM
31. C O M M U N I T Y 0 50 100 150 200 Patches MapReduce Storm Yarn Spark 0 10000 20000 30000 40000 Lines Added MapReduce Storm Yarn Spark 0 3500 7000 10500 14000 Lines Removed MapReduce Storm Yarn Spark
32. S PA R K M O M E N T U M • 1.0 Released 5/30/2014 • Databricks investment $14MM Andreessen Horowitz • Partnerships with DataStax, Cloudera, MapR, Pivotal
33. Q & A
34. T H A N K S ! steve@aster.is @stevendborrelli