This gives a characterization of the machine learning computations and brings out the deficiencies of Hadoop 1.0. It gives the motivation for Hadoop YARN and a brief view of YARN architecture. It illustrates the power of specialized processing frameworks over YARN, such as Spark and GraphLab. In short, Hadoop YARN allows your data to be stored in HDFS and specialized processing frameworks may be used to process the data in various ways.

1. Beyond Hadoop Map-Reduce
Dr. Vijay Srinivas Agneeswaran,
Director and Head, Big-data R&D,
Innovation Labs, Impetus
1

2. Contents
Big Data Computations
Hadoop 2.0 (Hadoop
YARN)
Berkeley data
analytics stack
• BDAS Spark
• BDAS Discretized
Streams
Real-time
analytics
with Storm
PMML • PMML Primer
Scoring
for Naïve • Naïve Bayes Primer
Bayes
2

3. Big Data Computations
Computations/Operations
Giant 1 (simple stats) is perfect
for Hadoop 1.0.
Giants 2 (linear algebra), 3 (Nbody), 4 (optimization) Spark
from UC Berkeley is efficient.
Interactive/On-the-fly data
processing – Storm.
Logistic regression, kernel SVMs,
conjugate gradient descent,
collaborative filtering, Gibbs
sampling, alternating least squares.
Example is social group-first
approach for consumer churn
analysis [1]
OLAP – data cube operations.
Dremel/Drill
Data sets – not embarrassingly
parallel?
Machine vision from Google
Deep Learning
Artificial Neural Networks
Speech analysis from Microsoft
Giant 5 – Graph processing –
GraphLab, Pregel, Giraph
3
[1] National Research Council. Frontiers in Massive Data Analysis . Washington, DC: The National Academies Press, 2013.
[2] RICHTER, Yossi ; YOM-TOV, Elad ; SLONIM, Noam: Predicting Customer Churn in Mobile Networks through Analysis of
Social Groups. In: Proceedings of SIAM International Conference on Data Mining, 2010, S. 732-741

4. Hadoop YARN Requirements or 1.0 shortcomings
R1: Scalability
R2: Multi-tenancy
• single cluster limitation
• Addressed by Hadoopon-Demand
• Security, Quotas
R3: Locality
awareness
R4: Shared cluster
utilization
• Shuffle of records
• Hogging by users
• Typed slots
R5:
Reliability/Availability
• Job Tracker bugs
R6: Iterative
Machine Learning
4
Vinod Kumar Vavilapalli, Arun C Murthy , Chris Douglas, Sharad Agarwal, Mahadev Konar, Robert Evans, Thomas Graves,
Jason Lowe , Hitesh Shah, Siddharth Seth, Bikas Saha, Carlo Curino, Owen O'Malley, Sanjay Radia, Benjamin Reed, and
Eric Baldeschwieler, “Apache Hadoop YARN: Yet Another Resource Negotiator”, ACM Symposium on Cloud Computing,
Oct 2013, ACM Press.

5. 5
Hadoop YARN Architecture

6. YARN Internals
Application Master
• Sends
ResourceRequests
to the YARN RM
• Captures
containers,
resources per
container, locality
preferences.
YARN RM
• Generates tokens
and containers
• Global view of
cluster – monolithic
scheduling.
Node Manager
• Node health
monitoring,
advertise available
resources through
heartbeats to RM.
6

7. Berkeley Big-data Analytics Stack (BDAS)
7

8. BDAS: Spark
Transformations/Actions
Map(function f1)
Filter(function f2)
flatMap(function f3)
Union(RDD r1)
Sample(flag, p, seed)
groupByKey(noTasks)
Description
Pass each element of the RDD through f1 in parallel and return the resulting RDD.
Select elements of RDD that return true when passed through f2.
Similar to Map, but f3 returns a sequence to facilitate mapping single input to multiple
outputs.
Returns result of union of the RDD r1 with the self.
Returns a randomly sampled (with seed) p percentage of the RDD.
Can only be invoked on key-value paired data – returns data grouped by value. No. of
parallel tasks is given as an argument (default is 8).
Aggregates result of applying f4 on elements with same key. No. of parallel tasks is the
second argument.
Joins RDD r2 with self – computes all possible pairs for given key.
Joins RDD r3 with self and groups by key.
reduceByKey(function f4,
noTasks)
Join(RDD r2, noTasks)
groupWith(RDD r3,
noTasks)
sortByKey(flag)
Sorts the self RDD in ascending or descending based on flag.
Reduce(function f5)
Aggregates result of applying function f5 on all elements of self RDD
Collect()
Return all elements of the RDD as an array.
Count()
Count no. of elements in RDD
take(n)
Get first n elements of RDD.
First()
Equivalent to take(1)
saveAsTextFile(path)
Persists RDD in a file in HDFS or other Hadoop supported file system at given path.
saveAsSequenceFile(path Persist RDD as a Hadoop sequence file. Can be invoked only on key-value paired RDDs
)
that implement Hadoop writable interface or equivalent.
foreach(function f6)
Run f6 in parallel on elements of self Ankur
[MZ12] Matei Zaharia, Mosharaf Chowdhury, Tathagata Das,RDD. Dave, Justin Ma, Murphy McCauley, Michael
J. Franklin, Scott Shenker, and Ion Stoica. 2012. Resilient distributed datasets: a fault-tolerant abstraction for inmemory cluster computing. In Proceedings of the 9th USENIX conference on Networked Systems Design and
Implementation (NSDI'12). USENIX Association, Berkeley, CA, USA, 2-2.

9. BDAS: Use Cases
Ooyala
Conviva
Uses Cassandra for
video data
personalization.
Uses Hive for
repeatedly running
ad-hoc queries on
video data.
Pre-compute
aggregates VS onthe-fly queries.
Optimized ad-hoc
queries using Spark
RDDs – found Spark
is 30 times faster
than Hive
Moved to Spark for
ML and computing
views.
ML for connection
analysis and video
streaming
optimization.
9
Moved to Shark for on-the-fly
queries – C* OLAP aggregate
queries on Cassandra 130 secs, 60
ms in Spark
Yahoo
Advertisement
targeting: 30K nodes
on Hadoop Yarn
Hadoop – batch processing
Spark – iterative processing
Storm – on-the-fly processing
Content
recommendation –
collaborative
filtering

10. 10

11. Real-time Analytics: R over Storm
11

12. Real-time Analytics UC 1: Internet Traffic Analysis

13. Real-time Analysis UC2: Arrhythmia Detection
13

14. GraphLab: Ideal Engine for Processing Natural Graphs [YL12]
Goals – targeted at machine
learning.
• Model graph dependencies, be
asynchronous, iterative, dynamic.
Data associated with edges
(weights, for instance) and
vertices (user profile data, current
interests etc.).
Update functions – lives on each
vertex
Consistency is important in ML
algorithms (some do not even
converge when there are
inconsistent updates –
collaborative filtering).
• Transforms data in scope of vertex.
• Can choose to trigger neighbours (for
example only if Rank changes drastically)
• Run asynchronously till convergence –
no global barrier.
• GraphLab – provides varying level of
consistency. Parallelism VS consistency.
Implemented several algorithms,
including ALS, K-means, SVM,
Belief propagation, matrix
factorization, Gibbs sampling,
SVD, CoEM etc.
• Co-EM (Expectation Maximization)
algorithm 15x faster than Hadoop MR –
on distributed GraphLab, only 0.3% of
Hadoop execution time.
[YL12] Yucheng Low, Danny Bickson, Joseph Gonzalez, Carlos Guestrin, Aapo Kyrola, and Joseph M. Hellerstein. 2012. Distributed
GraphLab: a framework for machine learning and data mining in the cloud. Proceedings of the VLDB Endowment 5, 8 (April 2012), 716-727.

15. GraphLab 2: PowerGraph – Modeling Natural Graphs [1]
GraphLab could not
scale to Altavista web
graph 2002, 1.4B
vertices, 6.7B edges.
Powergraph provides
new way of
partitioning power law
graphs
• Most graph parallel
abstractions assume small
neighbourhoods – low
degree vertices
• But natural graphs
(LinkedIn, Facebook,
Twitter) – power law
graphs.
• Hard to partition power law
graphs, high degree
vertices limit parallelism.
• Edges are tied to
machines, vertices (esp.
high degree ones) span
machines
• Execution split into 3
phases:
• Gather, apply and
scatter.
Triangle counting on
Twitter graph
• Hadoop MR took 423
minutes on 1536 machines
• GraphLab 2 took 1.5
minutes on 1024 cores (64
machines)
[1] Joseph E. Gonzalez, Yucheng Low, Haijie Gu, Danny Bickson, and Carlos Guestrin (2012). "PowerGraph:
Distributed Graph-Parallel Computation on Natural Graphs." Proceedings of the 10th USENIX Symposium
on Operating Systems Design and Implementation (OSDI '12).

16. PMML Primer
Predictive Model Markup
Language
Developed by DMG (Data
Mining Group)
PMML offers a standard
to define a model, so that
a model generated in
tool-A can be directly
used in tool-B.
XML representation of a
model.
May contain a myriad of
data transformations
(pre- and post-processing)
as well as one or more
predictive models.
16

17. Naïve Bayes Primer
A simple probabilistic
classifier based on
Bayes Theorem
Given features
X1,X2,…,Xn, predict a
label Y by calculating
the probability for all
possible Y value
Likelihood
Normalization Constant
Prior
17

18. PMML Scoring for Naïve Bayes
Wrote a PMML based
scoring engine for
Naïve Bayes
algorithm.
This can theoretically
be used in any
framework for data
processing by
invoking the API
Deployed a Naïve
Bayes PMML
generated from R into
Storm / Spark and
Samza frameworks
Real time predictions
with the above APIs
18

19. Header
• Version and timestamp
• Model development
environment information
Data Dictionary
• Variable types, missing
valid and invalid values,
Data
Munging/Transformation
• Normalization, mapping,
discretization
Model
• Model specifi attributes
• Mining Schema
• Treatment for missing
and outlier values
• Targets
• Prior probability and
default
• Outputs
• List of computer output
fields
• Post-processing
• Definition of model
architecture/parameters.
19

20. PMML Scoring for Naïve Bayes
<DataDictionary numberOfFields="4">
<DataField name="Class" optype="categorical" dataType="string">
<Value value="democrat"/>
<Value value="republican"/>
</DataField>
<DataField name="V1" optype="categorical" dataType="string">
<Value value="n"/>
<Value value="y"/>
</DataField>
<DataField name="V2" optype="categorical" dataType="string">
<Value value="n"/>
<Value value="y"/>
</DataField>
<DataField name="V3" optype="categorical" dataType="string">
<Value value="n"/>
<Value value="y"/>
</DataField>
</DataDictionary>
(ctd on the next slide)
20

21. PMML Scoring for Naïve Bayes
<NaiveBayesModel modelName="naiveBayes_Model" functionName="classification"
threshold="0.003">
<MiningSchema>
<MiningField name="Class" usageType="predicted"/>
<MiningField name="V1" usageType="active"/>
<MiningField name="V2" usageType="active"/>
<MiningField name="V3" usageType="active"/>
</MiningSchema>
<Output>
<OutputField name="Predicted_Class" feature="predictedValue"/>
<OutputField name="Probability_democrat" optype="continuous" dataType="double"
feature="probability" value="democrat"/>
<OutputField name="Probability_republican" optype="continuous" dataType="double"
feature="probability" value="republican"/>
</Output>
<BayesInputs>
(ctd on the next page)
21

22. PMML Scoring for Naïve Bayes
22
<BayesInputs>
<BayesInput fieldName="V1">
<PairCounts value="n">
<TargetValueCounts>
<TargetValueCount value="democrat" count="51"/>
<TargetValueCount value="republican" count="85"/>
</TargetValueCounts>
</PairCounts>
<PairCounts value="y">
<TargetValueCounts>
<TargetValueCount value="democrat" count="73"/>
<TargetValueCount value="republican" count="23"/>
</TargetValueCounts>
</PairCounts>
</BayesInput>
<BayesInput fieldName="V2">
*
<BayesInput fieldName="V3">
*
</BayesInputs>
<BayesOutput fieldName="Class">
<TargetValueCounts>
<TargetValueCount value="democrat" count="124"/>
<TargetValueCount value="republican" count="108"/>
</TargetValueCounts>
</BayesOutput>

23. PMML Scoring for Naïve Bayes
Definition Of Elements:DataDictionary :
Definitions for fields as used in mining models
( Class, V1, V2, V3 )
NaiveBayesModel :
Indicates that this is a NaiveBayes PMML
MiningSchema : lists fields as used in that model.
Class is “predicted” field,
V1,V2,V3 are “active” predictor fields
Output:
Describes a set of result values that can be returned
from a model
23

24. PMML Scoring for Naïve Bayes
Definition Of Elements (ctd .. ) :BayesInputs:
For each type of inputs, contains the counts of
outputs
BayesOutput:
Contains the counts associated with the values of the
target field
24

25. PMML Scoring for Naïve Bayes
Sample Input
Eg1 - n y y n y y n n n n n n y y y y
Eg2 - n y n y y y n n n n n y y y n y
• 1st , 2nd and 3rd Columns:
Predictor variables ( Attribute “name” in element MiningField )
• Using these we predict whether the Output is Democrat or
Republican ( PMML element BayesOutput)
25

26. PMML Scoring for Naïve Bayes
• 3 Node Xeon Machines Storm cluster ( 8
quad code CPUs, 32 GB RAM, 32 GB
Swap space, 1 Nimbus, 2 Supervisors )
Number of records ( in
millions )
Time Taken (seconds)
0.1
4
0.4
7
1.0
12
2.0
21
10
129
25
310
26

27. PMML Scoring for Naïve Bayes
• 3 Node Xeon Machines Spark cluster( 8
quad code CPUs, 32 GB RAM and 32
GB Swap space )
Number of records ( in
millions )
Time Taken (
0.1
1 min 47 sec
0.2
3 min 35 src
0.4
6 min 40 secs
1.0
35 mins 17 sec
10
More than 3 hrs
27

28. Conclusion
• Beyond Hadoop Map-Reduce philosophy
• Optimization and other problems.
• Real-time computation
• Processing specialized data structures
• PMML scoring
• Spark for batch computations
• Spark streaming and Storm for real-time.
28
• Allows traditional analytical tools/algorithms to be
re-used.

29. Thank You!
Mail
LinkedIn
• vijay.sa@impetus.co.in
• http://in.linkedin.com/in/vijaysrinivasagneeswaran
Blogs
• blogs.impetus.com
Twitter
• @a_vijaysrinivas.