Real time Analytics with Apache Kafka and Apache Spark

Real time Analytics
with Apache Kafka and Spark
October 2014 Meetup
Organized by Big Data Hyderabad.
http://www.meetup.com/Big-Data-Hyderabad/
Rahul Jain
@rahuldausa

About Me
• Big data/Search Consultant
• 8+ years of learning experience.
• Worked (got a chance) on High volume
distributed applications.
• Still a learner (and beginner)

Quick Questionnaire
How many people know/work on Scala ?
How many people know/work on Apache Kafka?
How many people know/heard/are using Apache Spark ?

What we are going to
learn/see today ?
• Apache Zookeeper (Overview)
• Apache Kafka – Hands-on
• Apache Spark – Hands-on
• Spark Streaming (Explore)

What is Zookeeper
• An Open source, High Performance coordination
service for distributed applications
• Centralized service for
– Configuration Management
– Locks and Synchronization for providing coordination
between distributed systems
– Naming service (Registry)
– Group Membership
• Features
– hierarchical namespace
– provides watcher on a znode
– allows to form a cluster of nodes
• Supports a large volume of request for data retrieval
and update
• http://zookeeper.apache.org/
Source : http://zookeeper.apache.org

Zookeeper Use cases
• Configuration Management
• Cluster member nodes Bootstrapping configuration from a
central source
• Distributed Cluster Management
• Node Join/Leave
• Node Status in real time
• Naming Service – e.g. DNS
• Distributed Synchronization – locks, barriers
• Leader election
• Centralized and Highly reliable Registry

Zookeeper Data Model
 Hierarchical Namespace
 Each node is called “znode”
 Each znode has data(stores data in
byte[] array) and can have children
 znode
– Maintains “Stat” structure with
version of data changes , ACL
changes and timestamp
– Version number increases with each
changes

Let’s recall basic concepts of
Messaging System

Point to Point Messaging
(Queue)
Credit: http://fusesource.com/docs/broker/5.3/getting_started/FuseMBStartedKeyJMS.html

Publish-Subscribe Messaging
(Topic)
Credit: http://fusesource.com/docs/broker/5.3/getting_started/FuseMBStartedKeyJMS.html

Overview
• An apache project initially developed at LinkedIn
• Distributed publish-subscribe messaging system
• Designed for processing of real time activity stream data e.g. logs,
metrics collections
• Written in Scala
• Does not follow JMS Standards, neither uses JMS APIs
• Features
– Persistent messaging
– High-throughput
– Supports both queue and topic semantics
– Uses Zookeeper for forming a cluster of nodes
(producer/consumer/broker)
and many more…
• http://kafka.apache.org/

How it works
Credit : http://kafka.apache.org/design.html

Real time transfer
Broker does not Push messages to Consumer, Consumer Polls messages from Broker.
Consumer1
(Group1)
Consumer3
(Group2)
Kafka
Broker
Consumer4
(Group2)
Producer
Zookeeper
Consumer2
(Group1)
Update Consumed
Message offset
Queue
Topology
Topic
Topology
Kafka
Broker

Performance Numbers
Producer Performance Consumer Performance
Credit : http://research.microsoft.com/en-us/UM/people/srikanth/netdb11/netdb11papers/netdb11-final12.pdf

About Apache Spark
• Initially started at UC Berkeley in 2009
• Fast and general purpose cluster computing system
• 10x (on disk) - 100x (In-Memory) faster
• Most popular for running Iterative Machine Learning Algorithms.
• Provides high level APIs in
• Java
• Scala
• Python
• Integration with Hadoop and its eco-system and can read existing data.
• http://spark.apache.org/

So Why Spark ?
• Most of Machine Learning Algorithms are iterative because each iteration
can improve the results
• With Disk based approach each iteration’s output is written to disk making
it slow
Hadoop execution flow
Spark execution flow
http://www.wiziq.com/blog/hype-around-apache-spark/

Spark Stack
• Spark SQL
– For SQL and unstructured data
processing
• MLib
– Machine Learning Algorithms
• GraphX
– Graph Processing
• Spark Streaming
– stream processing of live data
streams
http://spark.apache.org

Execution Flow
http://spark.apache.org/docs/latest/cluster-overview.html

Terminology
• Application Jar
– User Program and its dependencies except Hadoop & Spark Jars bundled into a
Jar file
• Driver Program
– The process to start the execution (main() function)
• Cluster Manager
– An external service to manage resources on the cluster (standalone manager,
YARN, Apache Mesos)
• Deploy Mode
– cluster : Driver inside the cluster
– client : Driver outside of Cluster

Terminology (contd.)
• Worker Node : Node that run the application program in cluster
• Executor
– Process launched on a worker node, that runs the Tasks
– Keep data in memory or disk storage
• Task : A unit of work that will be sent to executor
• Job
– Consists multiple tasks
– Created based on a Action
• Stage : Each Job is divided into smaller set of tasks called Stages that is sequential
and depend on each other
• SparkContext :
– represents the connection to a Spark cluster, and can be used to create RDDs,
accumulators and broadcast variables on that cluster.

Resilient Distributed Dataset (RDD)
• Resilient Distributed Dataset (RDD) is a basic Abstraction in Spark
• Immutable, Partitioned collection of elements that can be operated in parallel
• Basic Operations
– map
– filter
– persist
• Multiple Implementation
– PairRDDFunctions : RDD of Key-Value Pairs, groupByKey, Join
– DoubleRDDFunctions : Operation related to double values
– SequenceFileRDDFunctions : Operation related to SequenceFiles
• RDD main characteristics:
– A list of partitions
– A function for computing each split
– A list of dependencies on other RDDs
– Optionally, a Partitioner for key-value RDDs (e.g. to say that the RDD is hash-partitioned)
– Optionally, a list of preferred locations to compute each split on (e.g. block locations for an HDFS file)
• Custom RDD can be also implemented (by overriding functions)

Cluster Deployment
• Standalone Deploy Mode
– simplest way to deploy Spark on a private cluster
• Amazon EC2
– EC2 scripts are available
– Very quick launching a new cluster
• Apache Mesos
• Hadoop YARN

Let’s start getting hands dirty

Kafka Installation
• Download
– http://kafka.apache.org/downloads.html
• Untar it
> tar -xzf kafka_<version>.tgz
> cd kafka_<version>

Start Servers
• Start the Zookeeper server
> bin/zookeeper-server-start.sh config/zookeeper.properties
Pre-requisite: Zookeeper should be up and running.
• Now Start the Kafka Server
> bin/kafka-server-start.sh config/server.properties

Create/List Topics
• Create a topic
> bin/kafka-topics.sh --create --zookeeper localhost:2181 --
replication-factor 1 --partitions 1 --topic test
• List down all topics
> bin/kafka-topics.sh --list --zookeeper localhost:2181
Output: test

Producer
• Send some Messages
> bin/kafka-console-producer.sh --broker-list
localhost:9092 --topic test
Now type on console:
This is a message
This is another message

Consumer
• Receive some Messages
> bin/kafka-console-consumer.sh --zookeeper
localhost:2181 --topic test --from-beginning
This is a message
This is another message

Multi-Broker Cluster
• Copy configs
> cp config/server.properties config/server-1.properties
> cp config/server.properties config/server-2.properties
• Changes in the config files.
config/server-1.properties:
broker.id=1
port=9093
log.dir=/tmp/kafka-logs-1
config/server-2.properties:
broker.id=2
port=9094
log.dir=/tmp/kafka-logs-2

Start with New Nodes
• Start other Nodes with new configs
> bin/kafka-server-start.sh config/server-1.properties &
> bin/kafka-server-start.sh config/server-2.properties &
• Create a new topic with replication factor as 3
> bin/kafka-topics.sh --create --zookeeper
localhost:2181 --replication-factor 3 --partitions
1 --topic my-replicated-topic
• List down the all topics
> bin/kafka-topics.sh --describe --zookeeper
localhost:2181 --topic my-replicated-topic
Topic:my-replicated-topic PartitionCount:1 ReplicationFactor:3 Configs:
Topic: my-replicated-topic Partition: 0 Leader: 1 Replicas: 1,2,0 Isr: 1,2,0

Spark Shell
./bin/spark-shell --master local[2]
The --master option specifies the master URL for a distributed cluster, or local to run
locally with one thread, or local[N] to run locally with N threads. You should start by
using local for testing.
./bin/run-example SparkPi 10
This will run 10 iterations to calculate the value of Pi

Basic operations…
scala> val textFile = sc.textFile("README.md")
textFile: spark.RDD[String] = spark.MappedRDD@2ee9b6e3
scala> textFile.count() // Number of items in this RDD
ees0: Long = 126
scala> textFile.first() // First item in this RDD
res1: String = # Apache Spark
scala> val linesWithSpark = textFile.filter(line =>
line.contains("Spark"))
linesWithSpark: spark.RDD[String] = spark.FilteredRDD@7dd4af09
Simplier - Single liner:
scala> textFile.filter(line => line.contains("Spark")).count()
// How many lines contain "Spark"?
res3: Long = 15

Map - Reduce
scala> textFile.map(line => line.split(" ").size).reduce((a, b)
=> if (a > b) a else b)
res4: Long = 15
scala> import java.lang.Math
scala> textFile.map(line => line.split(" ").size).reduce((a, b)
=> Math.max(a, b))
res5: Int = 15
scala> val wordCounts = textFile.flatMap(line => line.split("
")).map(word => (word, 1)).reduceByKey((a, b) => a + b)
wordCounts: spark.RDD[(String, Int)] =
spark.ShuffledAggregatedRDD@71f027b8
wordCounts.collect()

With Caching…
scala> linesWithSpark.cache()
res7: spark.RDD[String] = spark.FilteredRDD@17e51082
scala> linesWithSpark.count()
res8: Long = 15
scala> linesWithSpark.count()
res9: Long = 15

With HDFS…
val lines = spark.textFile(“hdfs://...”)
val errors = lines.filter(line => line.startsWith(“ERROR”))
println(Total errors: + errors.count())

Standalone (Scala)
/* SimpleApp.scala */
import org.apache.spark.SparkContext
import org.apache.spark.SparkContext._
import org.apache.spark.SparkConf
object SimpleApp {
def main(args: Array[String]) {
val logFile = "YOUR_SPARK_HOME/README.md" // Should be some file on your
system
val conf = new SparkConf().setAppName("Simple Application")
.setMaster(“local")
val sc = new SparkContext(conf)
val logData = sc.textFile(logFile, 2).cache()
val numAs = logData.filter(line => line.contains("a")).count()
val numBs = logData.filter(line => line.contains("b")).count()
println("Lines with a: %s, Lines with b: %s".format(numAs, numBs))
}
}

Standalone (Java)
/* SimpleApp.java */
import org.apache.spark.api.java.*;
import org.apache.spark.SparkConf;
import org.apache.spark.api.java.function.Function;
public class SimpleApp {
public static void main(String[] args) {
String logFile = "YOUR_SPARK_HOME/README.md"; // Should be some file on your system
SparkConf conf = new SparkConf().setAppName("Simple Application").setMaster("local");
JavaSparkContext sc = new JavaSparkContext(conf);
JavaRDD<String> logData = sc.textFile(logFile).cache();
long numAs = logData.filter(new Function<String, Boolean>() {
public Boolean call(String s) { return s.contains("a"); }
}).count();
long numBs = logData.filter(new Function<String, Boolean>() {
public Boolean call(String s) { return s.contains("b"); }
}).count();
System.out.println("Lines with a: " + numAs + ", lines with b: " + numBs);
}
}

Job Submission
$SPARK_HOME/bin/spark-submit
--class "SimpleApp"
--master local[4]
target/scala-2.10/simple-project_2.10-1.0.jar

Configuration
val conf = new SparkConf()
.setMaster("local")
.setAppName("CountingSheep")
.set("spark.executor.memory", "1g")
val sc = new SparkContext(conf)

Let’s discuss
Real-time Clickstream Analytics

Analytics High Level Flow
A clickstream is the recording of the parts
of the screen a computer user clicks on
while web browsing.
http://blog.cloudera.com/blog/2014/03/letting-it-flow-with-spark-streaming/

Spark Streaming
Makes it easy to build scalable fault-tolerant streaming
applications.
– Ease of Use
– Fault Tolerance
– Combine streaming with batch and interactive queries.

Support Multiple Input/Outputs
Credit : http://spark.apache.org

Streaming Flow
Credit : http://spark.apache.org

Spark Streaming Terminology
• Spark Context
– An object with configuration parameters
• Discretized Steams (DStreams)
– Stream from input sources or generated after transformation
– Continuous series of RDDs
• Input DSteams
– Stream of raw data from input sources

Spark Context
SparkConf sparkConf = new SparkConf().setAppName(”PageViewsCount");
sparkConf.setMaster("local[2]");//running locally with 2 threads
// Create the context with a 5 second batch size
JavaStreamingContext jssc = new JavaStreamingContext(sparkConf, new Duration(5000));

Reading from Kafka Stream
int numThreads = Integer.parseInt(args[3]);
Map<String, Integer> topicMap = new HashMap<String, Integer>();
String[] topics = args[2].split(",");
for (String topic: topics) {
topicMap.put(topic, numThreads);
}
JavaPairReceiverInputDStream<String, String> messages =
KafkaUtils.createStream(jssc, <zkQuorum>, <group> , topicMap);

Processing of Stream
/**
* Incoming:
// (192.168.2.82,1412977327392,www.example.com,192.168.2.82)
// 192.168.2.82: key : tuple2._1()
// 1412977327392,www.example.com,192.168.2.82: value: tuple2._2()
*/
// Method signature: messages.map(InputArgs, OutputArgs)
JavaDStream<Tuple2<String, String>> events = messages.map(new Function<Tuple2<String, String>,
Tuple2<String, String>>() {
@Override
public Tuple2<String, String> call(Tuple2<String, String> tuple2) {
String[] parts = tuple2._2().split(",");
return new Tuple2<>(parts[2], parts[1]);
}
});
JavaPairDStream<String, Long> pageCountsByUrl = events.map(new Function<Tuple2<String,String>, String>(){
@Override
public String call(Tuple2<String, String> pageView) throws Exception {
return pageView._2();
}
}).countByValue();
System.out.println("Page counts by url:");
pageCountsByUrl.print();

Thanks!
@rahuldausa on twitter and slideshare
http://www.linkedin.com/in/rahuldausa
Join us @ For Solr, Lucene, Elasticsearch, Machine Learning, IR
http://www.meetup.com/Hyderabad-Apache-Solr-Lucene-Group/
http://www.meetup.com/DataAnalyticsGroup/
Join us @ For Hadoop, Spark, Cascading, Scala, NoSQL, Crawlers and all cutting edge technologies.
http://www.meetup.com/Big-Data-Hyderabad/

Real time Analytics with Apache Kafka and Apache Spark

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