详解通过docker和docker-compose实现eureka高可用

最近新项目有使用到springcloud 和docker，关于这两个技术就不分别介绍了，现在分享一下通过docker,docker-compose实现eureka高可用的方案。

1. eureka server项目目录结构：

2. eureka 配置文件配置：

server:
 port: 8900

spring:
 application:
  name: eureka-server
 profiles:
  active: dev

management:
 security:
  enabled: false
 health:
  rabbit:
   enabled: false

---
spring:
 profiles: dev

eureka:
 client:
  serviceUrl:
   defaultZone: http://localhost:${server.port}/eureka/
  register-with-eureka: false
  fetch-registry: false
 instance:
  hostname: localhost
  prefer-ip-address: true

---
spring:
 profiles: test_ha_1

eureka:
 client:
  serviceUrl:
   defaultZone: http://eurekaserver2:${server.port}/eureka/
 instance:
  hostname: eurekaserver1
#  prefer-ip-address: true 该配置为true表示注册到eureka上的是IP，如果这样的化，eureka服务器就不能通过服务器发现Replicas。
#               故如果想通过Docker实现eureka高可用，该配置最好使用默认值（false）
#               此处配置为true且实现高可用也不是没有办法，就是每个eureka服务需映射到Docker环境外，且知道ip。
---
spring:
 profiles: test_ha_2

eureka:
 client:
  serviceUrl:
   defaultZone: http://eurekaserver1:${server.port}/eureka/
 instance:
  hostname: eurekaserver2
#  prefer-ip-address: true

3. docker maven插件配置：

<build>
    <plugins>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
      </plugin>
      <plugin>
        <groupId>com.spotify</groupId>
        <artifactId>docker-maven-plugin</artifactId>
        <version>0.4.13</version>
        <configuration>
          <imageName>${docker.image.prefix}/${project.artifactId}:${project.version}</imageName>
          <dockerDirectory>src/main/docker</dockerDirectory>
          <forceTags>true</forceTags>
          <resources>
            <resource>
              <targetPath>/</targetPath>
              <directory>${project.build.directory}</directory>
            </resource>
          </resources>
        </configuration>
        <!--<groupId>com.spotify</groupId>
        <artifactId>docker-maven-plugin</artifactId>
        <version>0.4.13</version>
        <configuration>
          <imageName>itmuch/${project.artifactId}:${project.version}</imageName>
          <forceTags>true</forceTags>
          <baseImage>java</baseImage>
          <entryPoint>["java", "-jar", "/${project.build.finalName}.jar"]</entryPoint>
          <resources>
            <resource>
              <targetPath>/</targetPath>
              <directory>${project.build.directory}</directory>
              <include>${project.build.finalName}.jar</include>
            </resource>
          </resources>
        </configuration>-->
      </plugin>
    </plugins>
  </build>

4. Docker file 文件内容：

FROM java:8

ADD eureka-server-1.0.0.jar eurekaserver.jar
ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom","-jar","/eurekaserver.jar"]

5. 生成 eureka server 镜像：

通过执行 mvn clean package docker:build 命令，生成eurekaserver镜像，如下：

6. 通过docker-compose 编排：

version: '2'
services:
 eurekaserver1:
  image: raynspace/eureka-server:1.0.0
  ports:
   - "7900:8900"
  environment:
   - spring.profiles.active=test_ha_1

 eurekaserver2:
  image: raynspace/eureka-server:1.0.0
  #hostname: eurekaserver2
  ports:
   - "7800:8900"
  environment:
   - spring.profiles.active=test_ha_2

7. 跳转至项目目录下，执行docker-compose up 命令，自动生成eureka server 两个容器：

8. 由于已经把eureka 端口映射出来，所以本地通过端口访问eureka，查看eureka 服务状态：

通过上图可知，在registered-replicas和available-replicas两项均能看见另外一个eureka服务，至此eureka 集群搭建完成。