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

前言:

必需學會SpringBoot基礎知識

簡介:

spring cloud 為開發人員提供了快速構建分布式系統的一些工具，包括配置管理、服務發現、斷路器、路由、微代理、事件總線、全局鎖、決策競選、分布式會話等等。它運行環境簡單，可以在開發人員的電腦上跑。

工具:

JDK8

apache-maven-3.5.2

IntelliJ IDEA 2018.1 x64

 

上一篇文章講述了一個服務如何從配置中心讀取文件，配置中心如何從遠程git讀取配置文件，當服務實例很多時，都從配置中心讀取文件，這時可以考慮將配置中心做成一個微服務，將其集群化，從而達到高可用，架構圖如下：

                       

 

一、准備工作

繼續使用上一篇文章的工程，創建一個 eureka-config-server-cluster Project，用作服務注冊中心。

在 pom.xml File 引入 Eureka 的起步依賴 spring-cloud-starter-eureka-server，代碼如下:

<?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 ，指定服務端口為8889，配置服務注冊中心，代碼如下：

server:
  port: 8889

eureka:
  instance:
    hostname: localhost
  client:
    registerWithEureka: false
    fetchRegistry: false
    serviceUrl:
      defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/

啟動類:

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 的起步依賴 spring-cloud-starter-eureka-server，代碼如下:

<?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，指定服務注冊地址為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

並且啟動類添加@EnableConfigServer和@EnableEurekaClient的注解

 

三、修改 eureka-config-client

將其注冊微到服務注冊中心，作為Eureka客戶端，需要pom文件加上起步依賴spring-cloud-starter-eureka，代碼如下：

<?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。加上服務注冊地址為 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 是從配置中心讀取文件。

spring.cloud.config.discovery.serviceId 配置中心的servieId，即服務名。

 

這時發現，在讀取配置文件不再寫ip地址，而是服務名，這時如果配置服務部署多份，通過負載均衡，從而高可用。

依次啟動

1. eureka-config-server-cluster
2. eureka-config-server
3. eureka-config-client

訪問網址：http://localhost:8889/

 

訪問 http://localhost:8881/configs ，瀏覽器顯示：

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

 

四、源碼下載

標簽 7-1

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

 

五、踩過的坑

留意注解

 

六、理解

如果有親手做過的同學應該會發現, 我們是新建一個注冊中心, 再將配置服務端和配置客戶端一起注冊去中心,  其余的和第一篇的差不多一樣, 具體理解還是看個人, 師傅帶入門, 修行靠自己!