This is the slide deck from my June 2016 presentation on using gRPC and Cassandra to build high performance web services in an IoT enviroment

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In today's development ecosystem building a service oriented architecture based on a micro services is
common practice. With the rise of Big Data and Internet of Things applications making these services highly
performant services is no longer an option. In order to accomplish the scalability and performance
requirements that customers expect we are required to start thinking differently about how we architect and
build these applications in order to meet those demands.
This session will demonstrate a method for creating a highly performant service based application using
Google’s GRPC and Apache Cassandra in .NET. We will show how you can combine gRPC to minimize
communication overhead while leveraging Cassandra to optimize storage of time series data. We will explore
these concepts by creating an Internet of Things (IoT) application to demonstrate how you can effectively
meet the performance and scalability challenges posed by these new breeds of applications.
Abstract

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Performance is not an
Option
Building High performance Web Services
with gRPC and Cassandra
June 9th, 2016
#build4prfrmnc

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● What is gRPC
● What is Cassandra
● How to build a simple gRPC Microservice
● How to persist time series data in Cassandra
● Why you might want to use gRPC/Cassandra instead of a
more traditional REST/RDBMS for a Time-Series IoT
application
What I hope you take away

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Dave Bechberger
Senior Architect
dave@experoinc.com
@bechbd
https://www.linkedin.com/in/davebechberger
About me

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Expero - Bringing challenging product ideas to reality
Architecture &
Development
Product Strategy
User Experience
Domain
Expert

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Expero - Select Clients
6
Austin(HQ) • Houston • New York City • Founded 2003

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What is gRPC?
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● gRPC is a general purpose RPC
framework
● Built on standards
● Free and Open Source
● Built for distributed systems
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What is gRPC?

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● Allows client to call methods on
the server as if they were local
● Built for low latency highly
scalable microservices
● Payload agnostic
● Bi-Directional Streaming
● Pluggable and Extensible
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gRPC Architecture

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Simple Model and Service Definition

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Optimized Speed and Performance

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Code Generation

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What is Cassandra?
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What is Cassandra?
● Distributed Datastore
● Open Source Apache Project
● No Single Point of Failure
● Scalable
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CAP Theorem - Pick 2
● Consistency - all nodes see the same data
at the same time
● Availability - every requests receives a
response
● Partition Tolerant - the system continues
to operate even during network failures
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ACID vs. BASE
RDBMS World
● Atomic - transactions are “all or nothing”
● Consistency - On completion all data is
the same
● Isolated - transactions do not interfere
with one another
● Durable - results of a transaction are
permanent
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NoSQL World
● Base Availability - The datastore works
most of the time
● Soft State - Stores are not write
consistent, data can differ between
replicas
● Eventually Consistent - Stores become
consistent over time

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Cassandra Architecture
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Hash Ring Architecture
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● All nodes own a portion of the token
ring
● All nodes know which token ranges
belong to which nodes
● Partitioner generates a token from the
Partition Key
● Tokens determine where data is
located on the ring

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How Tokens Work
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Partitioner
Token:12
Client Driver
PK: Expero
Data Written

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Data Replication
● Data replication is automatic
● Number of replicas is called the Replication Factor or RF
● Data is replicated between Data Centers
● Hinted Handoff

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Data Replication in Action
Client
Write A
Data Written
Replica Written
Replica Written
Coordinator
Driver
Partitioner
Token:12
PK: Expero

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What does it mean to be Eventually Consistent?
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● Data will “eventually” match on all replicas, usually in terms of
milliseconds
● Consistency Level or CL (11 for writes, 10 for reads)
● Tuning consistency affects performance and availability
● CL can be tuned for R/W performance on a per query basis using CQL

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Why use Cassandra over your RDBMS?
● Performance
● Linearly Scalable
● Natively built as a distributed datastore
● Always-On Architecture
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What is DataStax vs. Apache Cassandra?
● Certified Cassandra – Delivers highest quality
Cassandra software for confidence and peace of
mind for production environments
● Enterprise Security – Full protection for sensitive
data
● Automatic Management Services – Automates
key maintenance functions to keep the database
running smoothly
● OpsCenter – Advanced management and
monitoring functionality for production applications
● Expert Support – Answers and assistance from the
Cassandra experts for all production needs
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The Problem - Engine Monitoring
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● Truck Engine Monitoring
Software
● Currently ~ 1000 trucks taking
readings every 10 seconds
● WebAPI REST on a SQL Server
2014 Database
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Setup

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● You were recently landed a huge
new client Expero Trucking Inc.
● Sensor readings now 1/second
and add geolocation (lat/long)
data
● Adding 10,000 trucks.
● Minimize costs and zero
downtime
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The Requirements

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● 100 measurements/second to
22,000 measurements/second
● Data load from ~35 MB/day to
~2.2 GB/day
● Your architecture needs to
change
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The Problem

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The Solution - gRPC and Cassandra
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Code Available Here https://github.com/experoinc/NDC-Oslo-2016/tree/master/NDC.Oslo

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● Change SQL Server Database to a Cassandra Cluster
● Replace REST based services with gRPC services
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Proposed Solution

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Defining a Model and Service

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Generating Client/Server Stubs
Model Definition Service Definition

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Creating Cassandra KeySpace and Table

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Connecting to Apache Cassandra using DataStax Driver
DataStax Open Source C# Driver - https://github.com/datastax/csharp-driver

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Writing Data to Cassandra

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Reading Data From Cassandra

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Time to See Some Running Code
Average Ping Time
Running in Oregon

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Tradeoffs of gRPC and Cassandra
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● Not for Browsers
● Chunk “Big” (>1MB ) Data
● No Nullable Data Types
● Not Production Yet
Tradeoffs of using gRPC

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● No joins between tables
● No Ad-Hoc queries
● Minimal Aggregations
● Complexity
● Cassandra is Not Relational
Tradeoffs of using Cassandra

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● gRPC
○ http://www.grpc.io/
○ https://developers.google.com/protocol-buffers/docs/proto3
● Cassandra
○ http://cassandra.apache.org/
○ http://www.planetcassandra.org/
○ https://academy.datastax.com/
○ http://www.datastax.com/
Learning More

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Thank you, any Questions?
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