Delivered by Martin McVay at Pivotal Meetup held at Skillsmatter London, 26 November 2015

1. 1© 2015 Pivotal Software, Inc. All rights reserved. 1© 2015 Pivotal Software, Inc. All rights reserved.
Microservices: Why and How?
Netflix OSS/Spring Cloud & Pivotal Cloud Foundry
Matt Stine (@mstine)
Principal Engineer & Senior Product Manager
August 2015

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DEFINE: Microservice
Loosely coupled service oriented
architecture with bounded contexts
If every service has to be updated in concert,
it’s not loosely coupled!
If you have to know about surrounding
services you don’t have a bounded context.

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Not Monoliths
Relational Database
Data Access
Service
HTML JavaScript MVC
Service
Monolithic ApplicationBrowser

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Not Traditional (ESB-centric) SOA
Enterprise Service Bus
Service Service Service Service
Service Service Service Service
UI UI

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But Microservices!

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But no Microservice is an Island…

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Example Distributed System: Minified

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Some emergent challenges of microservices
systems…
Ÿ Configuration Management
Ÿ Service Registration & Discovery
Ÿ Routing & Load Balancing
Ÿ Fault Tolerance (Circuit Breakers!)
Ÿ Monitoring

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Example: Coordination Boiler Plate

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• Eureka
• Hystrix + Turbine
• Ribbon
• Feign
• Zuul
http://netflix.github.io

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http://projects.spring.io/spring-cloud

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Example: Spring Cloud + Netflix OSS

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Config Server

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Config Server + Cloud Bus

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Service Registration/Discovery

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Service Registration/Discovery
@SpringBootApplication
@EnableCircuitBreaker
@EnableDiscoveryClient
public class CustomerApp extends RepositoryRestMvcConfiguration {
@Override
protected void configureRepositoryRestConfiguration(RepositoryRestConfiguration
config) {
config.exposeIdsFor(Customer.class);
}
public static void main(String[] args) {
SpringApplication.run(CustomerApp.class, args);
}
}

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Fault Tolerance – Circuit Breakers

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Fault Tolerance – Circuit Breakers
@SpringBootApplication
@EnableCircuitBreaker
@EnableDiscoveryClient
public class CustomerApp extends RepositoryRestMvcConfiguration {
@Override
protected void configureRepositoryRestConfiguration(RepositoryRestConfiguration
config) {
config.exposeIdsFor(Customer.class);
}
public static void main(String[] args) {
SpringApplication.run(CustomerApp.class, args);
}
}

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@HystrixCommand(fallbackMethod = "defaultLink")
public Link getStoresByLocationLink(Map<String, Object> parameters) {
URI storesUri = URI.create(uri);
try {
ServiceInstance instance = loadBalancer.choose("stores");
storesUri = URI.create(String.format("http://%s:%s",
instance.getHost(), instance.getPort()));
}
catch (RuntimeException e) {
// Eureka not available
}
Traverson traverson = new Traverson(storesUri, MediaTypes.HAL_JSON);
Link link = traverson.follow("stores", "search", "by-location")
.withTemplateParameters(parameters).asLink();
return link;
}
Enabling a Circuit Breaker
Client-Side Load Balancing

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{
"id" : 3,
"firstname" : "Matt",
"lastname" : "Stine",
"address" : {
"street" : "9195 East Mineral Circle",
"zipCode" : "80112",
"city" : "Centennial",
"location" : {
"latitude" : 39.5738106,
"longitude" : -104.8816934
}
},
"_links" : {
"self" : {
"href" : "http://pivotalcustomers.cfapps.io/customers/3"
},
"stores-nearby" : {
"href" : "http://pivotalstores.cfapps.io/stores/search/
findByAddressLocationNear?location=39.5738106,-104.8816934&distance=50"
}
}
}

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Circuit Breaker Fallback
public Link defaultLink(Map<String, Object> parameters) {
return null;
}
@HystrixCommand(fallbackMethod = "defaultLink")
public Link getStoresByLocationLink(Map<String, Object> parameters) {
//...
}

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{
"id" : 3,
"firstname" : "Matt",
"lastname" : "Stine",
"address" : {
"street" : "9195 East Mineral Circle",
"zipCode" : "80112",
"city" : "Centennial",
"location" : {
"latitude" : 39.5738106,
"longitude" : -104.8816934
}
},
"_links" : {
"self" : {
"href" : "http://pivotalcustomers.cfapps.io/customers/3"
}
}
}

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http://highscalability.com/blog/2014/4/8/microservices-not-a-free-lunch.html

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Paying for your lunch…
Ÿ Significant Operations Overhead
Ÿ Substantial DevOps Skills Required
Ÿ Implicit Interfaces
Ÿ Duplication of Effort
Ÿ Distributed System Complexity
Ÿ Asynchronicity is Difficult!
Ÿ Testability Challenges

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You must be this tall
to use
Microservices…
https://www.flickr.com/photos/gusset/3723961589
• RAPID PROVISIONING
• BASIC MONITORING
• RAPID APPLICATION DEPLOYMENT
• DEVOPS CULTURE
http://martinfowler.com/bliki/MicroservicePrerequisites.html

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It takes a platform…
Cloud Foundry Spring Cloud
Services

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Cloud Foundry Features
Ÿ Environment Provisioning
Ÿ On-Demand/Automatic Scaling
Ÿ Failover/Resilience
Ÿ Routing/Load Balancing
Ÿ Data Service Operations
Ÿ Monitoring

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Spring Cloud Services Suite
Spring Cloud Services
Config Server Service Registry Circuit Breaker
Dashboard

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Datastore
Message
Bus
Circuit Breaker
Load Balancer
Message
Bus
REST Workload
(Customer)
Circuit Breaker
Load Balancer
REST Workload
(Stores)
Datastore
Message
Bus
UI (Angular)
Circuit Breaker
Load Balancer
Production
Ready
Proxy
Service
Discovery
Config Server
Messaging
Circuit Breaker
Dashboard
Circuit Breaker
Metric
Aggregation
Bind
Production
Ready
Production
Ready
PCF Applications
PCF Services
Spring Cloud Services Suite – Logical View

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Spring Cloud Services Suite
• Installed via Pivotal Ops Manager
• Adds all services to Pivotal Cloud Foundry
Marketplace
• Dependencies:
• MySQL for PCF
• RabbitMQ for PCF
Spring Cloud
Services

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App Manager Marketplace

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Spring Cloud Config Server
Config Server
• Spring Cloud Config Server
• Service Binding via Spring Cloud
Connector
• Git/SVN URL for Config Repo provided
via Service Dashboard (post-
provisioning)
• Single tenant, scoped to CF space
(nothing prevents shared Git repo)

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Spring Cloud Config Server Dashboard

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Spring Cloud Service Registry
Service Registry
• Service Registration and Discovery via
Netflix OSS Eureka
• Service Binding via Spring Cloud Connector
• Single-tenant, scoped to CF space
• Registration via CF Route or DEA/Cell
IP:Port (must enable cross-container traffic)

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Spring Cloud Service Registry Dashboard

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Spring Cloud Services Suite
Circuit Breaker
Dashboard
• Netflix OSS Turbine + Hystrix Dashboard
• Aggregation via AMQP (RabbitMQ)
• Binding via Spring Cloud Connector
• Single-tenant, scoped to CF space

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Spring Cloud Services Roadmap
Ÿ Opinionated RBAC via OAuth2 / Integration with PCF UAA
Ÿ Spring Cloud Bus Refresh/Restart (as a Service)
Ÿ Spring Cloud Config Server Encryption/Decryption
Ÿ Policy-based Inter-org/space Service Discovery
Ÿ Distributed Tracing
Ÿ Spring Cloud Dataflow (Spring XD 2.0)
Ÿ API Gateway / Management (as a Service)
Ÿ Polyglot Language Support (via Sidecar)
Ÿ .NET Support (Native Bindings)

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Policy-based Inter-org/space Service Discovery

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μServices
with
Bindable Services
In-App Support Libraries
BETA
MAY 2015

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Published March 16, 2015
Available to you compliments
of Pivotal!
http://bit.ly/cloud-native-book