Eureka学习

2023-11-17 10:22:22

Eureka学习

介绍

Eureka 是一款开源的服务注册与发现组件，通过配合其他组件可提供负载均衡能力

名称	类型	AP/CP	语言	依赖	集成	一致性算法
Eureka	General	AP	java	jvm	Java Client
Zookeeper	General	CP	java		Client Bingding	paxos
cnosul	General	CP	go	jvm	HTTP/DNS library	Raft

CAP理论：

C（Consistency）：数据一致性，当存在多个副本的情况下，由于网络，机器故障，程序内部错误等原因出现数据写入副本成功部分，这种情况下会出现数据的不一致，一致性的要求是在对数据的更新完成后，多个副本的数据是一一致的

A（Availability）：客户端在对集群进行读写的时候，能够正常请求，但是数据的更新最终结果会有延迟，即在一定的时间内完成，也就是最终一致性

P（Partition Tolerrance）：分区容忍性，即发生通信故障时，一个集群本分为多个无法互相通信的分区时，集群仍然可用

创建Eureka Server

在POM.xml增加依赖：spring-cloud-starter-netflix-eureka-server

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.5.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>spring-boot2</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>8</java.version>
        <spring-cloud.version>Finchley.RELEASE</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-server</artifactId>
            <version>2.2.3.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <!--devtools热部署-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
            <scope>true</scope>
        </dependency>
    </dependencies>

    <build>
        <defaultGoal>compile</defaultGoal>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <includeSystemScope>true</includeSystemScope>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

启动类的增加SpringBoot2Application2

package com.example.demo;

/**
 * @author felix_cai
 *
 */
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@SpringBootApplication
@EnableEurekaServer
public class SpringBoot2Application2 {
    public static void main(String[] args) {
        SpringApplication.run(SpringBoot2Application2.class, args);
    }
}

修改application.properties文件

# 要注册的服务名
spring.application.name=EurekaServer
# 端口
server.port=8761
#不向注册中心注册实例，因为该实例本身就是注册中心
eureka.client.register-with-eureka=false
#不从Eureka Server 中获取实例信息
eureka.client.fetch-registry=false

启动服务

http://127.0.0.1:8761/

创建Eureka Provider

修改pom.xml

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.5.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>spring-boot2</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>8</java.version>
        <spring-cloud.version>Finchley.RELEASE</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>
            <version>2.2.3.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <!--devtools热部署-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
            <scope>true</scope>
        </dependency>
    </dependencies>
    <build>
        <defaultGoal>compile</defaultGoal>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <includeSystemScope>true</includeSystemScope>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

修改application.properties文件

# 要注册的服务名
spring.application.name=Eureka-provider
# 端口
server.port=8762
#Eureka Server地址信息
eureka.client.service-url.defaultZone=http://localhost:8761/eureka

码农公寓

Eureka学习

介绍

创建Eureka Server

创建Eureka Provider

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