Real time-hadoop

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© 2014 MapR Technologies 1© 2014 MapR Technologies

Real-time Hadoop:The Ideal Messaging System for HadoopTed Dunning

© 2014 MapR Technologies 2

Contact Information

Ted DunningChief Applications Architect at MapR Technologies

Committer & PMC for Apache’s Drill, Zookeeper & othersVP of Incubator at Apache Foundation

Email tdunning@apache.org tdunning@maprtech.com

Twitter @ted_dunning

Hashtags today: #stratahadoop #ojai

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Don’t Miss These• Just-in-time optimizing a database

– Me! at 4:20 PM, Room 230 C, today• Why flow instead of state?

– Me! at 5:10 PM, Room 210 D/H, today• High Frequency Decisioning

– Jack Norris! at 11:00 PM, Room 210 B/F, tomorrow• Threat detection on streaming data

– Carol Macdonald! at 3:45 PM, Solutions Theater, tomorrow• Scaling Your Business … Zeta Architecture

– Jim Scott! at 5:10 PM, Room 210 D/H, tomorrow

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And Also, a Little Fun

Come jam with us

The Big Data Boys and the Real-time Stream Band5:50 PM, MapR booth, today

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Goals• Real-time or near-time

– Includes situations with deadlines– Also includes situations where delay is simply undesirable– Even includes situations where delay is just fine

• Micro-services– Streaming is a convenient idiom for design– Micro-services … you know we wanted it– Service isolation is a key requirement

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Real-time or Near-time?• The real point is flow versus state (see talk later today)

• One consequence of flow-based computing is real-time and near-time become relatively easy

• Life may be a bitch, but it doesn’t happen in batches!

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Agenda• Background / micro-services

• Global requirements

• Scale

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A microservice is

loosely coupledwith bounded context

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How to Couple Services and Break micro-ness• Shared schemas, relational stores• Ad hoc communication between services• Enterprise service busses• Brittle protocols• Poor protocol versioning

Don’t do this!

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How to Decouple Services• Use self-describing data • Private databases• Infrastructural communication between services• Use modern protocols• Adopt future-proof protocol practices

• Use shared storage where necessary due to scale

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What is the Right Structure for Flow Compute?• Traditional message queues?

– Message queues are classic answer– Key feature/bug is out-of-order acknowledgement– Many implementations– You pay a huge performance hit for persistence

• Kafka-esque Logs?– Logs are like queues, but with ordering– Out of order consumption is possible, acknowledgement not so much– Canonical base implementation is Kafka– Performance plus persistence

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ScenariosProfile Database

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The task

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Traditional Solution

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What Happens Next?

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What Happens Next?

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How to Get Service Isolation

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New Uses of Data

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Scaling Through Isolation

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Lessons• De-coupling and isolation are key• Private data stores/tables are important,

– but local storage of private data is a bug• Propagate events, not table updates

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ScenariosIoT Data Aggregation

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Basic Situation

Each location has many

pumps

Multiple locations

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What Does a Pump Look Like

TemperaturePressure

Flow

TemperaturePressureFlow

Winding temperature

VoltageCurrent

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Basic Situation

Each location has many

pumps

Multiple locations

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Basic Architecture Reflects Business Structure

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Lessons• Data architecture should reflect business structure

• Even very modest designs involve multiple data centers

• Schemas cannot be frozen in the real world

• Security must follow data ownership

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ScenariosGlobal Data Recovery

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Lessons• Arbitrary number of topics important for simplicity + performance

• Updates happen in many places

• Mobility implies change in replication patterns

• Multi-master updates simplify design massively

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Converged Requirements

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What Have We Learned?• Need persistence and performance

– Possibly for years and to 100’s of millions t/s• Must have convergence

– Need files, tables AND streams– Need volumes, snapshots, mirrors, permissions and …

• Must have platform security– Cannot depend on perimeter– Must follow business structure

• Must have global scale and scope– Millions of topics for natural designs– Multi-master replication and update

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The Importance of Common API’s• Commonality and interoperability are critical

– Compare Hadoop eco-system and the noSQL world• Table stakes

– Persistence– Performance– Polymorphism

• Major trend so far is to adopt Kafka API– 0.9 API and beyond remove major abstraction leaks– Kafka API supported by all major Hadoop vendors

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What we do

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Evolution of Data Storage

FunctionalityCompatibility

Scalability

LinuxPOSIX

Over decades of progress,Unix-based systems have set the standard for compatibility and functionality

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FunctionalityCompatibility

Scalability

LinuxPOSIX

HadoopHadoop achieves much higher scalability by trading away essentially all of this compatibility

Evolution of Data Storage

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Evolution of Data Storage

FunctionalityCompatibility

Scalability

LinuxPOSIX

Hadoop

MapR enhanced Apache Hadoop by restoring the compatibility while increasing scalability and performance

FunctionalityCompatibility

Scalability

POSIX

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FunctionalityCompatibility

Scalability

LinuxPOSIX

Hadoop

Evolution of Data Storage

Adding tables and streams enhances the functionality of the base file system

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http://bit.ly/fastest-big-data

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How we do this with MapR• MapR Streams is a C++ reimplementation of Kafka API

– Advantages in predictability, performance, scale– Common security and permissions with entire MapR converged data

platform• Semantic extensions

– A cluster contains volumes, files, tables … and now streams– Streams contain topics– Can have default stream or can name stream by path name

• Core MapR capabilities preserved– Consistent snapshots, mirrors, multi-master replication

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MapR core Innovations• Volumes

– Distributed management– Data placement

• Read/write random access file system– Allows distributed meta-data– Improved scaling– Enables NFS access

• Application-level NIC bonding• Transactionally correct snapshots and mirrors

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MapR's Containers

Each container contains Directories & files Data blocks

Replicated on servers No need to manage

directly

Files/directories are sharded into blocks, whichare placed into containers on disks

Containers are 16-32 GB segments of disk, placed on nodes

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MapR's Containers

Each container has a replication chain

Updates are transactional Failures are handled by

rearranging replication

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Container locations and replication

CLDB

N1, N2N3, N2N1, N2N1, N3N3, N2

N1

N2

N3Container location database (CLDB) keeps track of nodes hosting each container and replication chain order

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MapR ScalingContainers represent 16 - 32GB of data

Each can hold up to 1 Billion files and directories 100M containers = ~ 2 Exabytes (a very large cluster)

250 bytes DRAM to cache a container 25GB to cache all containers for 2EB cluster

But not necessary, can page to disk Typical large 10PB cluster needs 2GB

Container-reports are 100x - 1000x < HDFS block-reports Serve 100x more data-nodes Increase container size to 64G to serve 4EB cluster

Map/reduce not affected

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But Wait, There’s More• Directories and files are implemented in terms of B-trees

– Key is offset, value is data blob– Internal transactional semantics guarantees safety and consistency– Layout algorithms give very high layout linearization

• Tables are implemented in terms of B-trees– Twisted B-tree implementation allows virtues of log-structured merge tree

without the compaction delays– Tablet splitting without pausing, integration with file system transactions

• Common security and permissions scheme

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And More …• Streams are implemented in terms of B-trees as well

– Topics and consumer offsets are kept in stream, not ZK– Similar splitting technology as MapR DB tables – Consistent permissions, security, data replication

• Standard Kafka 0.9 API• Plans to add OJAI for high-level structuring

• Performance is very high

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Example

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Lessons• API’s matter more than implementations

• There is plenty of room to innovate ahead of the community

• Posix, HDFS, HBASE all define useful API’s

• Kafka 0.9+ does the same

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Call to action:

Support the Kafka API’s

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Call to action:

Support the Kafka API’s

And come by the MapR boothto check out MapR Streams

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Short Books by Ted Dunning & Ellen Friedman• Published by O’Reilly in 2014 - 2016• For sale from Amazon or O’Reilly• Free e-books currently available courtesy of MapR

http://bit.ly/ebook-real-world-hadoop

http://bit.ly/mapr-tsdb-ebook

http://bit.ly/ebook-anomaly

http://bit.ly/recommendation-ebook

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Streaming Architectureby Ted Dunning and Ellen Friedman © 2016 (published by O’Reilly)

Free copies at book signing today

http://bit.ly/mapr-ebook-streams

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Thank You!

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Q & A@mapr maprtech

tdunning@maprtech.com

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