Microservices with Spring Boot and Spring Cloud

Spring Boot makes creating small Java application easy - and also facilitates operations and deployment. But for Microservices need more: Because Microservices are a distributed systems issues like Service Discovery or Load Balancing must be solved. Spring Cloud adds those capabilities to Spring Boot using e.g. the Netflix stack. This talks covers Spring Boot and Spring Cloud and shows how these technologies can be used to create a complete Microservices environment.

Transcript

1. Microservices with Java, Spring Boot & Spring Cloud Eberhard Wolff Fellow, innoQ @ewolff
3. http://microservices-buch.de/ http://microservices-book.com/
4. http://microservices-book.com/primer.html FREE!!!!
5. Microservice Definition
6. Server Server Microservices: Definition > Small > Independent deployment units > Any technology > Any infrastructure Micro Service Micro Service
7. Components Collaborate Micro Service Micro Service Link Data Replication REST Messaging
8. Infrastructure > …must support lots of services > Easy to create a new project > REST integrated > Messaging supported > Uniform operations
9. Spring Boot Demo
10. Simple Infrastructure > One pom.xml > …or Gradle / Ant > Very few dependencies > One plug in > Versions defined
11. REST Integrated > Support in Spring MVC > As we have seen > Also: JAX-RS > Jersey
12. Messaging Support > Numerous Spring Boot Starter > AMQP (RabbitMQ) > HornetQ (JMS) > ActiveMQ Artemis (JMS)
13. Messaging Support > Spring JMS abstraction > Message driven POJOs > Scalable > Simplify sending JMS > Can use other libs, too! > Boot: everything Spring / Java can do
14. Infrastructure > …must support lots of services > Easy to create a new project > REST integrated > Messaging supported > Simple deployment > Uniform operations ✓ ✓ ✓
15. Deploy > Package everything in an executable JAR > …or a WAR > Based on Maven, Ant or Gradle > Add configuration
16. Spring Boot Deploy Demo
17. Deploy > Install a basic machine > Install Java > Copy over JAR > Optional: Make it a Linux Service > …just a link > Optional: Create application.properties
18. Infrastructure > …must support lots of services > Easy to create a new project > REST integrated > Messaging supported > Simple deployment > Uniform operations ✓ ✓ ✓ ✓
19. Spring Boot Actuator > Provide information about the application > Via HTTP / JSON > …or Metrics > Can be evaluated by monitoring tools etc. > E.g. Graphite, Grafana ….
20. Spring Boot Actuator Demo
21. > https://github.com/ewolff/user-registration-V2 > Logging ELK > Subdir log-analysis > Monitoring Graphite > Subdir graphite
22. Infrastructure > …must support lots of services > Easy to create a new project > REST integrated > Messaging supported > Simple deployment > Uniform operations ✓ ✓ ✓ ✓ ✓
23. Spring Cloud
24. Based on Spring Boot
25. Supports many technology stacks, Clouds, …
26. Focus: Netflix Stack
27. Spring Cloud Netflix Zuul Routing Ribbon Client Side Load Balancing Eureka Service Discovery Hystrix Resilience
28. Coordinating Microservices
29. > Must find each other Microservice Microservice
30. Service Discovery Eureka
31. Why Eureka? > REST based service registry > Supports replication > Caches on the client > Resilient > Fast > …but not consistent > Foundation for other services
32. Eureka Client in Spring Cloud > @EnableDiscoveryClient: generic > @EnableEurekaClient: more specific > Dependency to spring-cloud-starter-eureka > Automatically registers application
33. application.properties eureka.client.serviceUrl.defaultZone=http://host:8761/eureka/ eureka.instance.leaseRenewalIntervalInSeconds=5 spring.application.name=catalog eureka.instance.metadataMap.instanceId=${spring.application.name}:${r andom.value} eureka.instance.preferIpAddress=true Eureka server Can include user / password Need unique ID Load balancing Faster updates Dockerwon’t resolve host names Used for registration In CAPITAL caps
34. Eureka Server @EnableEurekaServer @EnableAutoConfiguration public class EurekaApplication { public static void main(String[] args) { SpringApplication.run(EurekaApplication.class, args); } } Add dependency to spring-cloud-starter-eureka-server
36. > Must find each other > Route calls to a service Microservice Microservice
37. Zuul Routing
38. Routing > One URL to the outside > Internal: Many Microservices > In particular: REST > Power through filters
39. Customer Order Catalog Zuul Proxy Automatically maps route to server registered on Eureka i.e. /customer/** to CUSTOMER No configuration Can add filters etc
40. Zuul Proxy @SpringBootApplication @EnableZuulProxy public class ZuulApplication { public static void main(String[] args) { new SpringApplicationBuilder(ZuulApplication.class). web(true).run(args); } } Enable Zuul Proxy Can change route Also routing to external services possible
41. > Must find each other > Route calls to a service > Configuration Microservice Microservice
42. Spring Cloud Config
43. Configuration > Spring Cloud Config > Central configuration > Dynamic updates > Can use git backend > I prefer immutable server > & DevOps tools (Docker, Chef…)
44. Spring Cloud Bus > Pushed config updates > …or individual message > I prefer a messaging solution > Independent from Spring
45. > Must find each other > Route calls to a service > Configuration > Security Microservice Microservice
46. Spring Cloud Security
47. Spring Cloud Security > Single Sign On via OAuth2 > Forward token e.g. via RestTemplate > Support for Zuul > Very valuable!
48. Implementing Microservices
49. Microservice Microservice > Load Balancing
50. Load Balancing Ribbon
51. Proxy Load Balancing > Centralized Load Balancing > Can become bottle neck > Single point of failure > Configuration complex Load Balancer Server Client
52. Client Ribbon: Client Side Load Balancing > Decentralized Load Balancing > No bottle neck > Resilient > Can consider response time > Data might be inconsistent Load Balancer Server
53. RestTemplate & Load Balancing @RibbonClient(name = "ribbonApp") … public class RibbonApp { @Autowired private RestTemplate restTemplate; public void callMicroService() { Store store = restTemplate. getForObject("http://stores/store/1", Store.class); } Enable Ribbon Left out other annotations Eureka name or server list Standard Spring REST client Can also use Ribbon API
54. Microservice Microservice > Load Balancing > Resilience
55. Hystrix Resilience
56. Hystrix > Enable resilient applications > Do call in other thread pool > Won’t block request handler > Can implement timeout
57. Hystrix > Circuit Breaker > If call system fail open > If open do not forward call > Forward calls after a time window > System won’t be swamped with requests
58. Hystrix / Spring Cloud > Annotation based approach > Annotations of javanica libraries > Java Proxies automatically created > Simplifies Hystrix dramatically > No commands etc
59. @HystrixCommand(fallbackMethod = "getItemsCache") public Collection<Item> findAll() { … this.itemsCache = pagedResources.getContent(); return itemsCache; } private Collection<Item> getItemsCache() { return itemsCache; } Fallback
60. Stream via http Circuit Breaker status Thread Pool status
61. Conclusion
62. Infrastructure > Easy to create a new project > REST integrated > Messaging supported > Simple deployment > Uniform operations
63. Spring Cloud > Eureka: Service Discovery > Zuul: Route calls to a service > Spring Cloud Config: Configuration > Ribbon: Load Balancing > Hystrix: Resilience
64. Links > https://github.com/ewolff/microservices > https://github.com/ewolff/spring-boot-demos > https://github.com/ewolff/user-registration-V2 > http://projects.spring.io/spring-boot/ > http://projects.spring.io/spring-cloud > https://spring.io/guides/ > http://microservices-book.com
65. Thank You!! @ewolff