Spring Cloud Eureka学习笔记

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用于服务的注册于发现

由两个组件组成

1. Eureka Server 注册中心
2. Eureka Client 服务注册

Eureka Server(服务注册中心)

先创建一个springboot项目，添加依赖的时候选择如下

pom文件如下

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>

<groupId>com.cloud</groupId>
<artifactId>eureka</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<name>eureka</name>
<description>Demo project for Spring Boot</description>

<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.5.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>

<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
<spring-cloud.version>Finchley.SR1</spring-cloud.version>
</properties>

<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
</dependency>

<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>

<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>

<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>

</project>

添加@EnableEurekaServer注解,启动一个服务注册中心提供给其他应用进行对话

@SpringBootApplication
@EnableEurekaServer
public class EurekaApplication {

public static void main(String[] args) {
SpringApplication.run(EurekaApplication.class, args);
}
}

[/code]

除此之外还需要添加配置文件

eureka:
client:
service-url:
defaultZone: http://localhost:8761/eureka/
#由于注册中心会将自己作为客户端尝试注册自己,关闭客户端注册行为
register-with-eureka: false
#eureka的自我保护(只在开发环境关闭)
server:
enable-self-preservation: false
spring:
application:
name: eureka
server:
port: 8761

运行后,访问http://localhost:8761/可以看到如下页面:

Eureka Client 服务提供方

同样,先创建一个springboot项目,添加依赖的时候选择

pom文件如下,注意添加web的依赖,默认是没有添加的

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>

<groupId>com.cloud</groupId>
<artifactId>client</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<name>client</name>
<description>Demo project for Spring Boot</description>

<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.5.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>

<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
<spring-cloud.version>Finchley.SR1</spring-cloud.version>
</properties>

<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>

<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>

<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>

<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>

</project>

同样添加@EnableDiscoveryClient注解

@SpringBootApplication
@EnableDiscoveryClient
public class ClientApplication {

public static void main(String[] args) {
SpringApplication.run(ClientApplication.class, args);
}
}

[/code]

添加配置文件

eureka:
client:
service-url:
#指定注册中心的地址
defaultZone: http://localhost:8761/eureka/
#  instance:
#    hostname: clientname
spring:
application:
name: client

运行项目,在之前的Eureka页面可以看到,服务被注册进来了

Eureka Server 高可用

双节点注册中心

两个Eureka注册中心互相注册,client在两个注册中心都进行注册

配置文件如下:

Eureka1:

eureka:
client:
service-url:
defaultZone: http://localhost:8762/eureka/
#不让eureka出现在注册中心
register-with-eureka: false
#eureka的自我保护(只在开发环境关闭)
server:
enable-self-preservation: false
spring:
application:
name: eureka

Eureka2:

eureka:
client:
service-url:
defaultZone: http://localhost:8761/eureka/
#不让eureka出现在注册中心
register-with-eureka: false
#eureka的自我保护(只在开发环境关闭)
server:
enable-self-preservation: false
spring:
application:
name: eureka

client:

eureka:
client:
service-url:
defaultZone: http://localhost:8761/eureka/,http://localhost:8762/eureka/
#  instance:
#    hostname: clientname
spring:
application:
name: client

启动Eureka1，Eureka2,再启动client一段时间之后,client的服务会注册到两个注册中心

三节点注册中心

同上,三个Eureka两两注册,client同时注册三个

Eureka1:

eureka:
client:
service-url:
defaultZone: http://localhost:8762/eureka/, http://localhost:8763/eureka/
#不让eureka出现在注册中心
register-with-eureka: false
#eureka的自我保护(只在开发环境关闭)
server:
enable-self-preservation: false
spring:
application:
name: eureka

Eureka2:

eureka:
client:
service-url:
defaultZone: http://localhost:8761/eureka/, http://localhost:8763/eureka/
#不让eureka出现在注册中心
register-with-eureka: false
#eureka的自我保护(只在开发环境关闭)
server:
enable-self-preservation: false
spring:
application:
name: eureka

Eureka3:

eureka:
client:
service-url:
defaultZone: http://localhost:8761/eureka/, http://localhost:8762/eureka/
#不让eureka出现在注册中心
register-with-eureka: false
#eureka的自我保护(只在开发环境关闭)
server:
enable-self-preservation: false
spring:
application:
name: eureka

client:

eureka:
client:
service-url:
defaultZone: http://localhost:8761/eureka/,http://localhost:8762/eureka/,http://localhost:8763/eureka/
#  instance:
#    hostname: clientname
spring:
application:
name: client

服务发现的两种方式

1. 客户端发现
   Eureka
2. 服务端发现
   nginx
   • zookeeper
   • kubernetes

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