Download - Cassandra Day NY 2014: Message Architectures in Distributed Systems at SimpleReach

Eric Lubow

@elubow

[email protected]

Message

Architectures in Distributed

Systems

mailto:[email protected]

Message Architectures in Distributed Systems Eric Lubow @elubow

Overview

• SimpleReach

• Why is messaging important

• Goals

• Explanations

• Questions


Personal Vanity

• CTO of SimpleReach

• Co-author of Practical Cassandra

• Skydiver, Mixed Martial Artist,

Motorcyclist, Dog dad, NY Giants fan

• IronMatt Foundation for Pediatric Brian

Tumors (ironmatt.org)

http://ironmatt.org




• Millions of URLs per day

• Over 3.75 billion page views per month

• 7b events per day (~80k events/second)

• Auto-scale 175-190 machines depending on traffic

• Built a predictive measurement algorithm for the social web

SimpleReach


Why is Messaging Important?

• Most large scale systems discussions only talk about storage

• Direct high volumes of data around your infrastructure

• Control flow of data through your infrastructure

• Decouple important systems

• Scalability, Elasticity, Deliverability, and Redundancy

• Buffering and Asynchronous communication


The database is NOT a transport layer

App

❶

❹

❸

❷

incoming request

sync persist data

send response

async queue message

Data Flow

Message Architectures in Distributed Systems Eric Lubow @elubow #ddtx14


Goals• Consistent interfaces between systems

• Allow access to many toolsets

• Minimize downtime/Minimize cost of downtime

• High availability

• Clients should have minimal architecture knowledge

• Horizontal Scaling

• Controlled Data Flow Patterns

• Enrichment/In-stream Modification Schemes

• Monitoring and Instrumentation


Messaging Systems

• RabbitMQ

• ZeroMQ

• Kafka

• Amazon SQS

• NSQ

• ActiveMQ

• Resque

• Custom


What Did SimpleReach Choose?



NSQ• Distributed and de-centralized topology

• At least once delivery guaranteed

• Multicast style message routing

• Simple to configure and deploy

• Allow for maintenance windows with no downtime

• Ephemeral channels for testing

• Channel sampling

github.com/bitly/nsq


separate hosts

• a topic is a distinct stream of messages (a single nsqd instance can have multiple topics)

• a channel is an independent queue for a topic (a topic can have multiple channels)

• consumers discover producers by querying nsqlookupd (a discovery service for topics)

• topics and channels are created at runtime (just start publishing/subscribing)

nsqd

“metrics”

Channels

“event”

Topics

“enrichment”

“writer”

Consumers

AAABBB


Topics and Channels


Everyone Speaks The Same Language

http:// + {“content-type”: “application/json”}





• nsqadmin provides a web interface to administrate and introspect an NSQ cluster at runtime (and empty, pause, or delete topics/channels)

• nsq_to_http - utility that helps transport an aggregate stream over HTTP

• nsq_to_file - utility that safely persists an aggregated stream to disk

• nsq_stat - iostat like utility for a topic/channel

• nsq_tail - tail like utility for a topic/channel

NSQ Tools



Right Tool For The Job





NSQNSQD

API

consumer

NSQNSQD

API

NSQNSQD

API

consumer

nsqlookupd

nsqlookupd

PUBLISH

REGISTER

DISCOVER

SUBSCRIBE

How Does It Work?



The Schrute of the Problem







Simple Deployment & Automation

• Chef cookbook - github.com/simplereach/chef-nsq

• Written in Go

• Easily distributable binaries

• Deploy lookup nodes

• Nsqd’s installed locally

http://github.com/simplereach/chef-nsq








nsqlookupd nsqlookupd

consumer➊ regularly poll for topic producers

➋ connect to all producers

HTTP requests

Runtime Discovery










Path of a Packet

Internet

EC

Inte

rn

al

AP

I

Solr

C*

Mongo

Redis

Vertica

API

Fire Hose

SC

Co

ns

um

ers

Qu

eu

e



Controlled Data Flow

Social Event

CollectorSocial Data

Batch & Write

Processed Data

Batch & Write

Raw Data

Calculate Score Write

NSQ Broadcast NSQ



Social Event


Batch & Write

Processed Data

Batch & Write

Raw Data


NSQ Broadcast NSQ


Broadcast Importance for Polyglottany

Aggregator

Mongo Writer

Broadcast

Redis Writer

Cassandra Writer

Solr Writer

Calculator

NSQ

Vertica Writer




Social Event


Batch & Write

Processed Data

Batch & Write

Raw Data


NSQ Broadcast NSQ








• Controlled Data Flow


What Is Enrichment?

A mechanism to add value to a message to enhance processing in

your system


How Do We Enrich

Raw EventEnriched

Event

Consumer A

Consumer B

Consumer C

NSQ Broadcast









• Enrichment


Monitoring / Instrumentation

• Comes with statsd support built-in

• Statsd talks to both Graphite and nsqadmin

• Nsqadmin comes with graphs for message processing stats

• Nagios plugins available for monitoring topic/channel depth

• Average end to end latency calculations are done on a per-channel basis









• Enrichment

• Monitoring and Instrumentation


Summary• Large Systems are more than just storage

• Abstraction

• Highly Available

• Controlled Data Flow Patterns

• Monitoring & Automation


We’re

Hiring


Questions are guaranteed in life.

Answers aren’t.

Eric Lubow

@elubow

[email protected]

Cassandra Day, New York

Thank you.

mailto:[email protected]