Springcloud value Eureka

Spring Cloud Features

Conventions better than configuration

Off-the-box, quick Start

For a variety of environments PC Server Cloud Environment container (Docker)

Lightweight Component Services Discovery Eureka

Support for components is rich and fully functional configuration Center Registry Intelligent routing

Selection neutral service found Eureka Zookeeper Consul

About the version of Spring cloud

Most of the spring software versions are in: Major version. Minor version. Incremental version. The form of the milestone version is named

Spring Cloud Angel SR6???

Why Eureka?

Eureka from the production environment

Spring Cloud support for Eureka is good Https://github.com/netflix/eureka

Eureka Introduction

Eureka is a service discovery framework developed by Netflix, itself a rest-based service primarily used to locate middle-tier services running in an AWS domain for load balancing and middle-tier service failover purposes.

Spring Cloud integrates it into its subproject Spring-cloud-netflix to implement the service discovery capabilities of Spring Cloud.

The Eureka project is quite active, code updates are fairly frequent, 2.0 leads to better extensibility, and the use of a fine-grained subscription model replaces the pull-based model.

Eureka principle

The relationship between region and zone

-The application service is equivalent to the services provider (user microservices) in this book, application client is equivalent to the service consumer in this book (film MicroServices);
-Make Remote call, which can be simply understood as calling a restful interface
-US-EAST-1C, US-EAST-1D, etc. are zone, they belong to the region of Us-east-1

Eureka consists of two components: Eureka Server and Eureka Client

Eureka Server provides service registration services, and after each node is started, it is registered in Eureka server so that the service registry in Eureka server stores information for all available service nodes.

The information of the service node can be seen visually in the interface.

The Eureka client is a Java client that simplifies the interaction with Eureka server, and the client also has a built-in load balancer that uses a polling (round-robin) load algorithm.

After the app starts, the heartbeat is sent to Eureka Server (the default period is 30 seconds). If Eureka server does not receive a heartbeat for a node during multiple heartbeat cycles, Eureka server will

This service node is removed from the registry (default 90 seconds).

The synchronization of the data will be done through replication between Eureka servers.

Eureka also provides a mechanism for client caching , and even if all Eureka servers are hung up, clients can still consume the information in the cache for other services ' APIs

In conclusion, Eureka ensures high availability, flexibility and scalability through the mechanisms of heartbeat detection, health check, and client-side caching.

Service Registration Form

The service registry is a database that records the network information of the currently available service instances and is at the heart of the service discovery mechanism. The Service registry provides query APIs and management APIs, uses the query API to obtain available service instances, and uses the management API to implement registration and logoff

Service registration: The service's network address is registered in the service registry when the service is started

Health Check: The Service Discovery component detects registered services through some mechanism and removes the service from the service registry if it finds that a service is inaccessible (possibly after a few heartbeat cycles).

Springcloud value Eureka