Decomposing Applications for Scalability and Deployability (April 2...

Ad

Ad

Ad

Ad

Ad

Ad

Ad

Ad

Ad

Ad

Ad

Ad

Decomposing applications for
deployability and scalability
Chris Richardson

Author of POJOs in Action
Founder of the o...

Presentation goal

Decomposing applications
to improve deployability
and scalability
and
How Cloud Foundry...

About Chris

3

(About Chris)

4

About Chris()

5

About Chris

6

About Chris

http://www.theregister.co.uk/2009/08/19/springsource_cloud_foundry/

...

vmc push About-Chris

Developer Advocate for
CloudFoundry.com

Signup at http://cloudfoundry.com

Promo code: ...

Agenda
§ The (sometimes evil) monolith
§ Decomposing applications into services
§ How do services communicate?
§ Prese...

Let’s imagine you are building an e-
commerce application

10

Traditional web application architecture

WAR

...

But there are problems

12

Users expect a rich, dynamic and
interactive experience on mobile
devices and desktop
...

One dimensional scalability
§ Scales to handle transaction volumes
§ Higher transaction rate required run more instances...

Components that don’t cluster
§ Most application components are easily clustered:
• Most services are stateless
• S...

Obstacle to frequent deployments
§ Need to redeploy everything to change one component
§ Interrupts long running backgro...

Large application

Slow IDE
Slow start times for web container

17

Scaling development
WAR

StoreFrontUI

Accounting
Sca...

Long-term commitment to a single technology stack
§ Let’s suppose you go with the JVM
• Some polyglot support
• Man...

Agenda
§ The (sometimes evil) monolith
§ Decomposing applications into services
§ How do services communicate?
§ Prese...

3 dimensions to scaling

Y axis -
functional
decomposition

Scale by

...

X axis scaling - application level

Load WAR
Balancer

Tomcat

...

X axis scaling - database level
Writes Consistent reads

MySQL
...

Benefits and drawbacks of X axis splits
§ Benefits
• Easy and fast to implement
• Handles increasing transaction vo...

Z axis scaling - data partitioning
§ Each server runs the identical code base
§ Different servers responsible for differ...

Z axis scaling - database sharding
Partition column

RESTAURANT table

ID ...

Z axis scaling - application example
Content Query

Update Router ...

Benefits and drawbacks of Z axis splits
§ Benefits
• Each server only deals with a subset of the data
• Improved ca...

Y axis scaling - functional partitioning
§ Splits monolithic application into a set of services
§ Each service implement...

Y axis scaling - application level
billing web application

...

Y axis scaling - databases
Application

MySQL MySQL
...

Real world examples

http://techblog.netﬂix.com/

Between 100-150 services are acces...

Benefits and drawbacks of Y axis splits
§ Benefits
• Scales development: focussed two pizza devops teams
• Deploy s...

Two levels of architecture
§ System level
• Defines the inter-service glue: interfaces and
communication mechanisms...

If services are small...
§ Regularly rewrite using a better technology stack
§ Pick the best developers rather than best...

Moreover: you are not the same you ...
§ Cell lifetimes: Can we build software
• hours - s...

Agenda
§ The (sometimes evil) monolith
§ Decomposing applications into services
§ How do services communicate?
§ Prese...

Inter-service communication options
§ Multiple collaborating services need a communication
mechanism
§ Many choices...

Synchronous communication
wgrus-billing.war

Accounting
...

Service discovery options
§ Clients need to know the coordinates of their dependencies

§ Option #1: Caller is configu...

Benefits and drawbacks
§ Benefits
• Simple to implement and use
§ Drawbacks
• Poor fault isolation: caller is bloc...

Asynchronous message-based communication
wgrus-billing.war

...

Benefits and drawbacks
§ Benefits
• Decouples caller from server
• Caller unaware of server’s coordinates (URL)
...

Shared databases?

Order Management Customer Management

Database

...

Benefits and drawbacks
§ Benefits
• Simple
• Single (consistent) source of data
§ Drawbacks
• Defeats the purpo...

Better: separate databases

Customer Update Event
Order Management Cust...

Maintaining consistency without 2PC
begin transaction
update order tables
save intent to update customer tables
commit t...

Writing code that calls services

48

Composable futures
§ Problem:
• Service A needs to call services B and C and then D
• Makes sense to call B and C p...

Spring Integration

§ Builds on Spring framework
§ High-level of abstraction for building message
based applications
§...

Spring Integration concepts

§ Message channel
• Virtual pipe connecting producer and consumer
§ Message endpoints
•...

Spring Integration insulates
components from the underlying
communication mechanism

...

Example of reconfigurability - local
@Service
public class OrderServiceImpl { @Service
...

Example of reconfigurability - distributed

Code unchanged in new deployment

...

Handling failure
§ Errors happen (especially in distributed systems)
§ Use timeouts and retries
• Never wait forever
...

Agenda
§ The (sometimes evil) monolith
§ Decomposing applications into services
§ How do services communicate?
§ Prese...

Modular application

Choice of presentation layer technology
+
Redeploy UI frequently/independently...

NodeJS is the fashionable technology

Many JavaScript client frameworks have a NodeJS counterpart
e.g. socket.io

...

NodeJS isn’t the only game in town

JVM-based http://vertx.io/

...

A modern web application

Service 1
RESTful WS ...

Alternatively: multiple front-end servers

Node JS Service 1

Browser

HTML 5 ...

NodeJS - using RESTful WS and AMQP

REST
Service

Requests

...

Updating the UI is easy
§ Update the UI independently of rest of system
§ Easily run A/B tests
§ Enables fast iteration...

But coordination with backend changes required
§ Let’s imagine that you are deploying an advanced search
feature:
•...

Agenda
§ The (sometimes evil) monolith
§ Decomposing applications into services
§ How do services communicate?
§ Prese...

The challenge
§ In the beginning:
• It would be easy to use Y axis/functional decomposition
• But you don’t need it...

Lower cost way to start with Y axis decomposition
§ Enforce boundaries between services, e.g. DTOs
§ But run in a single...

Special case: Components that don’t cluster

Application

Monitoring Rest of domain classe...

Don’t let this happen!

Use well-defined interfaces

Ensure loose coupling

69

Traditional application architecture
Monolithic application

Service A Service B Serv...

Extracting a service = untangling dependencies
Application Service

...

Untangling dependencies
§ Domain object is part of an association class A {
• Read only - replicate ...

Bounded context is a useful idea
§ Different parts of a system different domain models
§ Different services have a diffe...

Untangling dependencies 1
Service A Service B Service C

Domain model 1 ...

Untangling dependencies 2
Service A Service B Service C

Domain model 1 ...

Untangling dependencies 3
Service A Service B Service C

Domain model 1 ...

Agenda
§ The (sometimes evil) monolith
§ Decomposing applications into services
§ How do services communicate?
§ Prese...

Traditional tools: monolithic applications

78

Developing service-oriented apps is harder
§ Many more moving parts to manage
• Infrastructure services: SQL, NoSQL, R...

Cloud Foundry makes it easier
§ Easy to deploy applications
§ Easy to provision services
§ Manifest describes the struc...

Services available on Cloud Foundry

81

Creating a service instance
$ vmc create-service mysql --name mysql1
Creating Service: OK

$ vmc services
......

========...

Multi-application manifest - part 1
---
applications:
inventory/target: Path to application
name: inv...

Multi-application manifest - part 2
store/target: Path to application
name: store
url: cer-store.ch...

One command to create services and deploy application
$ vmc push
Would you like to deploy from the current directory? [Y...

Application configuration via environment variables

$ vmc env-add cf1
PAYMENT_SVC=http://...
Adding Environment V...

Micro Cloud Foundry: new developer sandbox

App Instances Services

Open sou...

Using Caldecott…
$ vmc tunnel
1: mysql-135e0
2: mysql1
Which service to tunnel to?: 2
Password: ********
Stopping Applicat...

…Using Caldecott
Launching 'mysql --protocol=TCP --host=localhost --port=10000 --
user=uMe6Apgw00AhS --password=pKcD76...

Running JUnit test with Caldecott

Conﬁgure your test code to use port + connection info

...

Summary
§ Monolithic applications are simple to develop and deploy

BUT applying the scale cube

§ Deco...

@crichardson crichardson@vmware.com

Questions?
www.cloudfoundry.com promo code CFOpenTour2012

Share Slideshare

LinkedIn
Facebook
Twitter

Embed

Size (px)

Show related Slideshows at end

WordPress Shortcode

Link

Share
Email

Velocity 2014 - From Hero to Zero by Jennifer Davis 2676 views

View on Slideshare

1 of 92 Ad

View on Slideshare

1 of 92 Ad