使用Docker Compose编排Spring Cloud微服务

文章目录

• 微服务构建实例
• 简化Compose的编写
• 编排高可用的Eureka Server
• 编排高可用Spring Cloud微服务集群及动态伸缩

微服务项目名称	项目微服务中的角色
microservice-discovery-eureka	服务发现组件
microservice-provider-user	服务提供者
microservice-consumer-movie-ribbon-hystrix	服务消费者
microservice-gateway-zuul	API Gateway
microservice-hystrix-turbine	Hystrix聚合监控工具
microservice-hystrix-dashboard	Hystrix监控界面

微服务构建实例

1：使用Maven插件构建镜像，在各个项目的pom.xml中添加如下内容。

<!-- 添加docker-maven插件 -->
<plugin>
	<groupId>com.sptify</groupId>
	<artifactId>docker-maven-plugin</artifactId>
	<version>0.4.13</version>
	<configuration>
		<imageName>itmuch/${project.artifactId}:${project.version}</imageName>
		<forceTages>true</forceTages>
		<baseImage>java</baseImage>
		<entryPoint>["java","-jar","/${project.build.finalName}.jar"]</entryPoint>
		<resoureces>
			<resourece>
				<targetPath>/</targetPath>
				<directory>${project.build.directory}</directory>
				<include>${project.build.finalName}.jar</include>
			</resource>
		</resources>
	</configuration>
</plugin>

由配置可知，构建出来的镜像名称是itmuch/各个微服务的artifactId:各个微服务的版本，例如：microservice-discovery-eureka:0.0.1-SNAPSHOT。

2：为Eureka Server所在容器配置一个主机名（如discover），并让各个微服务使用主机名访问Eureka Server。
将全部微服务eureka.client.serviceUrl.defaultZone修改成以下内容：

eureka:
	client:
		serviceUrl:
			defaultZone:http://discovery:8761/eureka/

3：在每一个项目的根目录执行如下命令，构建Docker镜像。

mvn clean package docker:build

4：编写docker-compose.yml

version: '3'
#Version 2 file format的固定写法，为project定义服务
services:
	#指定服务名称
	microservice-discovery-eureka:
		#指定服务所使用的镜像
		image: itmuch/microservice-discovery-eureka:0.0.1-SNAPSHOT
		#暴露端口信息
		ports:
			- "8761:8761"
	microservice-provider-user:
		image: itmuch/microservice-provider-user:0.0.1-SNAPSHOT
		#链接到microservice-discovery-eureka，这边使用的是SERVICE:ALIAS的形式
		links:
			-	microservice-disvoery-eureka:discovery
			-
	microservice-consumer-movie-ribbon-hystrix:
		image: itmuch/microservice-consumer-movie-ribbon-hystrix:0.0.1-SNAPSHOT
		links:
			-	microservice-disvoery-eureka:discovery
	microservice-gateway-zuul:
		image: itmuch/microservice-gateway-zuul:0.0.1-SNAPSHOT
		links:
			-	microservice-disvoery-eureka:discovery
	microservice-hystrix-dashboard:
		image: itmuch/microservice-hystrix-dashboard:0.0.1-SNAPSHOT
		links:
			-	microservice-disvoery-eureka:discovery
	microservice-hystrix-turbine:
		image: itmuch/microservice-hystrix-turbine:0.0.1-SNAPSHOT
		links:
			-	microservice-disvoery-eureka:discovery

测试，执行docker-compose up启动项目，便可看到Eureka Server上的微服务列表服务发布成功。

简化Compose的编写

同一个Compose工程中的全部服务共享一个隔离网络，可以使用服务名称做为主机名来发现其余服务。

所以，将docker-compose.yml简化：

version: '2'
services:
	discovery:
		image: itmuch/discovery-eureka:0.0.1-SNAPSHOT
		ports:
			-	"8761:8761"
	microservice-provider-user:
		image: itmuch/microservice-provider-user:0.0.1-SNAPSHOT
	microservice-consumer-movie-ribbon-hystrix:
		image: itmuch/microservice-consumer-movie-ribbon-hystrix:0.0.1-SNAPSHOT
	microservice-gateway-zuul:
		image: itmuch/microservice-gateway-zuul:0.0.1-SNAPSHOT
	microservice-hystrix-dashboard:
		image: itmuch/microservice-hystrix-dashboard:0.0.1-SNAPSHOT
	microservice-hystrix-turbine:
		image: itmuch/microservice-hystrix-turbine:0.0.1-SNAPSHOT

编排高可用的Eureka Server

使用Compose编排Eureka Server集群。

1.执行如下命令构建Dokcer镜像。

mvn clean package docker:build

2.编写docker-compose.yml

version: '3'
services:
	microservice-discovery-eureka-ha1:
		hostname: peer1   #指定hostname
		image: itmuch/discovery=eureka-ha:0.0.1:SNAPSHOT
		links:
			-	discovery-eureka-ha2
		ports:
			-	"8761:8761"
		environment:
			-	spring.profiles.active=peer1
	microservice-discovery-eureka-ha2:
		hostname: peer2   #指定hostname
		image: itmuch/discovery=eureka-ha:0.0.1:SNAPSHOT
		links:
			-	discovery-eureka-ha1
		ports:
			-	"8762:8762"
		environment:
			-	spring.profiles.active=peer2

3.执行如下命令启动项目。

docker-compose up

可是，这样并不会成功，终端会输出异常。
由于存在循环依赖，links没法实现双向链接。
如何解决呢？ 例如使用 ambassador pattern，使用外部DNS容器等。

编排高可用Spring Cloud微服务集群及动态伸缩

微服务项目名称	项目微服务中的角色
microservice-discovery-eureka-ha	服务发现组件
microservice-provider-user	服务提供者
microservice-consumer-movie-ribbon-hystrix	服务消费者
microservice-gateway-zuul	API Gateway
microservice-hystrix-turbine	Hystrix聚合监控工具
microservice-hystrix-dashboard	Hystrix监控界面

1.因为使用了microservice-discovery-eureka-ha，须要将全部的微服务eureka.client.serviceUrl.defaultZone属性修改成以下内容：

eureka:
	client:
		service-url:
			defaultZone: http://peer1:8761/eureka/,http://peer2:8762/eureka/

2.在每一个项目的根目录，执行如下命令建立Docker镜像。

mvn clean package docker:build

3.编写docker-compose.yml

version: "2"
services:
	peer1:
		image: itemuch/microservice-discovery-eureka-ha:0.0.1-SNAPSHOT
		ports:
			-	"8761:8761"
		enviroment:
			-	spring.profiles.active=peer1
	peer2:
		image: itemuch/microservice-discovery-eureka-ha:0.0.1-SNAPSHOT
		hostname: peer2
		ports:
			-	"8761:8761"
		enviroment:
			-	spring.profiles.active=peer2
	microservice-provider-user:
		image: itmuch/microservice-provider-user:0.0.1-SNAPSHOT
	microservice-consumer-movie-ribbon-hystrix:
		image: itmuch/microservice-consumer-movie-ribbon-hystrix:0.0.1-SNAPSHOT
	microservice-gateway-zuul:
		image: itmuch/microservice-gateway-zuul:0.0.1-SNAPSHOT
	microservice-hystrix-dashboard:
		image: itmuch/microservice-hystrix-dashboard:0.0.1-SNAPSHOT
	microservice-hystrix-turbine:
		image: itmuch/microservice-hystrix-turbine:0.0.1-SNAPSHOT

测试，执行docker-compose up启动项目。

而后能够在Eureka Server看到微服务列表。

执行如下命令，为各个微服务动态扩容，让除Eureka Server之外的全部微服务都启动3个实例。

docker-compose scale microservice-provider-user=3 microservice-consumer-movie-ribbon-hystrix=3 microservice-gateway-zuul=3
microservice-hystrix-turbine=3