【SpringCloud】第七篇: 高可用的分布式配置中心(Spring Cloud Config)

前言:

必需学会SpringBoot基础知识

简介:

spring cloud 为开发人员提供了快速构建分布式系统的一些工具，包括配置管理、服务发现、断路器、路由、微代理、事件总线、全局锁、决策竞选、分布式会话等等。它运行环境简单，可以在开发人员的电脑上跑。

工具:

JDK8

apache-maven-3.5.2

IntelliJ IDEA 2018.1 x64

上一篇文章讲述了一个服务如何从配置中心读取文件，配置中心如何从远程git读取配置文件，当服务实例很多时，都从配置中心读取文件，这时可以考虑将配置中心做成一个微服务，将其集群化，从而达到高可用，架构图如下：

一、准备工作

继续使用上一篇文章的工程，创建一个 eureka-config-server-cluster Project，用作服务注册中心。

在 pom.xml File 引入 Eureka 的起步依赖 spring-cloud-starter-eureka-server，代码如下:

<?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.lwc</groupId>

	<artifactId>eureka-config-server-cluster</artifactId>

	<version>0.0.1-SNAPSHOT</version>

	<packaging>jar</packaging>

	<name>eureka-config-server-cluster</name>

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

	<parent>

		<groupId>org.springframework.boot</groupId>

		<artifactId>spring-boot-starter-parent</artifactId>

		<version>1.5.10.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>Edgware.SR3</spring-cloud.version>

	</properties>

	<dependencies>

		<dependency>

			<groupId>org.springframework.cloud</groupId>

			<artifactId>spring-cloud-starter-eureka-server</artifactId>

		</dependency>

		<dependency>

			<groupId>org.springframework.boot</groupId>

			<artifactId>spring-boot-starter-web</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>

在 application-dev.yml ，指定服务端口为8889，配置服务注册中心，代码如下：

server:

  port: 8889

eureka:

  instance:

    hostname: localhost

  client:

    registerWithEureka: false

    fetchRegistry: false

    serviceUrl:

      defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/

启动类:

package com.lwc;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

/**

 * @author Eddie

 */

@EnableEurekaServer

@SpringBootApplication

public class EurekaConfigServerClusterApplication {

    public static void main(String[] args) {

        SpringApplication.run(EurekaConfigServerClusterApplication.class, args);

    }

}

二、修改 eureka-config-server

在 pom.xml File 引入 Eureka 的起步依赖 spring-cloud-starter-eureka-server，代码如下:

<?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.lwc</groupId>

    <artifactId>eureka-config-server</artifactId>

    <version>0.0.1-SNAPSHOT</version>

    <packaging>jar</packaging>

    <name>eureka-config-server</name>

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

    <parent>

        <groupId>org.springframework.boot</groupId>

        <artifactId>spring-boot-starter-parent</artifactId>

        <version>1.5.10.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>Edgware.SR3</spring-cloud.version>

    </properties>

    <dependencies>

        <dependency>

            <groupId>org.springframework.cloud</groupId>

            <artifactId>spring-cloud-config-server</artifactId>

        </dependency>

        <dependency>

            <groupId>org.springframework.boot</groupId>

            <artifactId>spring-boot-starter-test</artifactId>

            <scope>test</scope>

        </dependency>

        <dependency>

            <groupId>org.springframework.cloud</groupId>

            <artifactId>spring-cloud-starter-eureka</artifactId>

        </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>

配置文件application-dev.yml，指定服务注册地址为http://localhost:8889/eureka/，其他配置同上一篇文章，完整的配置如下：

server:

  port: 8888

eureka:

  client:

    serviceUrl:

      defaultZone: http://localhost:8889/eureka/

spring:

  cloud:

    config:

      server:

        git:

          uri: https://github.com/eddie-code/SpringCloudDemo

          search-paths: config-repo

          username:

          passphrase:

      label: master

并且启动类添加@EnableConfigServer和@EnableEurekaClient的注解

三、修改 eureka-config-client

将其注册微到服务注册中心，作为Eureka客户端，需要pom文件加上起步依赖spring-cloud-starter-eureka，代码如下：

<?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.lwc</groupId>

    <artifactId>eureka-config-client</artifactId>

    <version>0.0.1-SNAPSHOT</version>

    <packaging>jar</packaging>

    <name>eureka-config-client</name>

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

    <parent>

        <groupId>org.springframework.boot</groupId>

        <artifactId>spring-boot-starter-parent</artifactId>

        <version>1.5.10.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>Edgware.SR3</spring-cloud.version>

    </properties>

    <dependencies>

        <dependency>

            <groupId>org.springframework.cloud</groupId>

            <artifactId>spring-cloud-starter-config</artifactId>

        </dependency>

        <dependency>

            <groupId>org.springframework.boot</groupId>

            <artifactId>spring-boot-starter-web</artifactId>

        </dependency>

        <dependency>

            <groupId>org.springframework.cloud</groupId>

            <artifactId>spring-cloud-starter-eureka</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>

    <repositories>

        <repository>

            <id>spring-milestones</id>

            <name>Spring Milestones</name>

            <url>https://repo.spring.io/milestone</url>

            <snapshots>

                <enabled>false</enabled>

            </snapshots>

        </repository>

    </repositories>

</project>

配置文件bootstrap-local.yml，注意是bootstrap。加上服务注册地址为 http://localhost:8889/eureka/

server:

  port: 8881

eureka:

  client:

    serviceUrl:

      defaultZone: http://localhost:8889/eureka/

spring:

  cloud:

    config:

      label: master

      profile: local

      discovery:

        serviceId: eureka-config-server

        enabled: true

spring.cloud.config.discovery.enabled 是从配置中心读取文件。

spring.cloud.config.discovery.serviceId 配置中心的servieId，即服务名。

这时发现，在读取配置文件不再写ip地址，而是服务名，这时如果配置服务部署多份，通过负载均衡，从而高可用。

依次启动

eureka-config-server-cluster
eureka-config-server
eureka-config-client

访问网址：http://localhost:8889/

访问 http://localhost:8881/configs ，浏览器显示：

This is local config Blog: http://www.cnblogs.com/EddieBlog/

四、源码下载

标签 7-1

https://github.com/eddie-code/SpringCloudDemo/tree/master/eureka-config-server-cluster

五、踩过的坑

留意注解

六、理解

如果有亲手做过的同学应该会发现, 我们是新建一个注册中心, 再将配置服务端和配置客户端一起注册去中心, 其余的和第一篇的差不多一样, 具体理解还是看个人, 师傅带入门, 修行靠自己!