Introduction to Spring Cloud Slack: #session-introduction-to-spring-cloud Olga Maciaszek-Sharma @olga_maciaszek Spencer Gibb @spencerbgibb

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Agenda • Cloud Native • Sample Architecture • Spring Cloud Components • Revisit Sample Architecture • Demo 3 

Cloud Native • Distributed • Scalable • Resilient • Automated • Organizational (Conway’s Law) • Replaceable 4 

Fallacies of Distributed Computing • The network is reliable. • Latency is zero. • Bandwidth is infinite. • The network is secure. • Topology doesn't change. • There is one administrator. • Transport cost is zero. • The network is homogeneous. https://web.archive.org/web/20071223073932/http://java.sys-con.com/read/38665.htm 5 

12 Factor Apps https://12factor.net 1.Code in VCS 2.Dependencies 3.Config in environment 4.Backing Services 5.Build, release, run 6.Process 6  7.Port binding 8.Concurrency 9.Disposability 10.Dev/prod parity 11.Logs 12.Admin processes See also the 1 Factor App and 15 Factor Apps

User Service Sample Architecture API Gateway Metrics Service Discovery Fraud Verifier Configuration Card Application Service

Distributed Configuration Service A Config Server Service B

Spring Cloud Config Server ● Pluggable ○ Git ○ Vault ○ Credhub ○ JDBC ○ IaaS resource (S3, etc…) ● Retry ● Spring Boot compatible client 9

Spring Cloud Consul Config ● Bring your own Consul ● Uses key-value store ● Can be on value per key or a file per key ● Can be auto-refreshed ● Spring Boot compatible client 1 0

Others ● Spring Cloud Vault ● Spring Cloud Zookeeper Config ● Direct to IaaS ○ Spring Cloud Alibaba ○ Spring Cloud AWS ○ Spring Cloud Azure ○ Spring Cloud GCP ● Platform ○ K8s config maps 1 1

Service A Service A Service Registration and Discovery Service A Service Registry Service B 1. Registers 2. Query for Service A instances 3. Connect

Netflix Eureka ● Provided by Spring Cloud Netflix ● Highly Available ● Eventually Consistent ● Netflix uses Spring Cloud Netflix! http://techblog.netflix.com/2012/09/eureka.html 1 3

Consul by Hashicorp ● Integration by Spring Cloud Consul ● Bring your own Consul Servers ● Can be strongly consistent ● Uses Services API ● Supports consul health checks ● Spring Boot compatible client 1 4

Others ● Spring Cloud Zookeeper Discovery ● Spring Cloud Alibaba (Nacos) 1 5

Client Side Load-balancer Service A Service A Service A Service Registry Service B 1. Query service A instances 2. Select the service A instance to send the request to Service A Service A Service A

Spring Cloud LoadBalancer ● Replaces Netflix Ribbon ● Pluggable algorithm ● Reactive support ● Extensible configuration 1 7

Failure Mitigation

Spring Cloud Circuit Breaker ● Protects from cascading failures ● Fallback ● Pluggable ○ Resilience4j ○ Spring Retry ○ Spring Cloud Alibaba (Sentinel) ● Pluggable algorithm ● Reactive support 1 9 Open Closed Half Open Failure threshold exceeded Success Timeout Reset Failure

Retry ● Retry failed requests ● Spring Retry ● Project Reactor ● Resilience4j 2 0

Distributed Tracing Browser API Gateway User Service Mobile App Cart Service Inventory Service Inventory DB User DB

Spring Cloud Sleuth ● Trouble-shooting across a distributed system ● Instruments for tracing ○ Spring Framework ○ Spring Boot ○ Spring Cloud 2 2

API Gateway Browser API Gateway User Service Mobile App Cart Service

Spring Cloud Gateway ● API Gateway ● Spring Boot App ● Focus on developer experience and customization ● Supports Spring Cloud ○ Configuration ○ Service Discovery ○ LoadBalancer ○ Retry/Circuit Breaker ○ Rate Limiting ○ Sleuth 2 4

User Service (SC Circuit Breaker) Sample Architecture with Spring Cloud Spring Cloud Gateway (SC CircuitBreaker, Retry) Metrics Eureka Service Discovery Fraud Verifier Spring Cloud Config Server Card Application Service (SC LoadBalancer)

Demo

What we did not talk about.

More to Spring Cloud ● Spring Cloud Bus ● Spring Cloud OpenFeign ● Spring Cloud Contract ● Spring Cloud Function ● Spring Cloud Stream ● Spring Cloud Task ● Spring Cloud Data Flow ● ... 2 8

Stay Connected. Slack: #session-introduction-to-spring-cloud https://github.com/spring-cloud-samples/spring-cloud-intro-demo https://github.com/spring-cloud https://spring.io/projects/spring-cloud Olga Maciaszek-Sharma @olga_maciaszek Spencer Gibb @spencerbgibb #springone @s1p