为什么要使用Docker Compose
可以使用Dockerfile(或Maven)构建镜像,使用微服务架构的应用系统一般包含若干个微服务,每个微服务一般有多个实例。如果每个微服务都要手动启停那么维护成本会非常高,docker compose只能控制当前主机的服务,无法控制集群
安装Compose
方法一:
# curl -L https://github.com/docker/compose/releases/download/1.8.1/docker-compose-`uname -s`-`uname -m` > /usr/local/bin/docker-compose # chmod +x /usr/local/bin/docker-compose 查看版本信息 # docker-compose --version 但是此方法会经常因为网络的原因而无法安装
方法二:
1、安装python-pip yum -y install epel-release yum -y install python-pip 2、安装docker-compose pip install docker-compose 待安装完成后,执行查询版本的命令,即可安装docker-compose docker-compose version
入门示例
1. mvn clean package microservice-discovery-eureka-0.0.1-SNAPSHOT.jar
2.microservice-discovery-eureka-0.0.1-SNAPSHOT.jar目录下创建Dockerfile文件
FROM java:8 VOLUME /tmp ADD microservice-discovery-eureka-0.0.1-SNAPSHOT.jar app.jar RUN bash -c 'touch /app.jar' EXPOSE 9000 ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom","-jar","/app.jar"]
3.microservice-discovery-eureka-0.0.1-SNAPSHOT.jar目录下创建docker-compose.yml
version: '3' # 表示该docker-compose.yml文件使用的是Version 2 file format services: # Version 2 file format的固定写法,为project定义服务。 microservice-discovery-eureka: # 指定服务名称 image: itmuch/microservice-discovery-eureka:0.0.1-SNAPSHOT # 指定服务所使用的镜像 ports: # 暴露端口信息 - "8761:8761"
4.在docker-compose.yml目录下执行以下命令:
docker-compose up -d # 在后台构建镜像并且启动容器
5.访问htthp://宿主机ip:8761 即可访问eureka server首页
docker-compose.yml常用命令
综合实战
编排SpingCloud微服务
1.使用Maven构建Docker镜像,各个项目pom文件添加以下代码
<!-- 添加spring-boot的maven插件 --> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> <!-- 添加docker-maven插件 --> <plugin> <groupId>com.spotify</groupId> <artifactId>docker-maven-plugin</artifactId> <version>0.4.13</version> <configuration> <imageName>itmuch/${project.artifactId}:${project.version}</imageName> <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>
2.编写 docker-compose.yml文件
version: '3' services: microservice-discovery-eureka: image: itmuch/microservice-discovery-eureka:0.0.1-SNAPSHOT network_mode: host ports: - 8761:8761 microservice-provider-user: image: itmuch/microservice-provider-user:0.0.1-SNAPSHOT network_mode: host ports: - 8000:8000 microservice-consumer-movie-ribbon-hystrix: image: itmuch/microservice-consumer-movie-ribbon-hystrix:0.0.1-SNAPSHOT network_mode: host ports: - 8010:8010 microservice-hystrix-dashboard: image: itmuch/microservice-hystrix-dashboard:0.0.1-SNAPSHOT network_mode: host ports: - 8030:8030 microservice-hystrix-turbine: image: itmuch/microservice-hystrix-turbine:0.0.1-SNAPSHOT network_mode: host ports: - 8031:8031 microservice-gateway-zuul: image: itmuch/microservice-gateway-zuul:0.0.1-SNAPSHOT network_mode: host ports: - 8040:8040 ## 注1:本Compose文件使用的网络模式是host,使用这种模式,可以让所有的微服务都无需修改eureka.client.serviceUrl.defautlZone的配置,而直接使用http://localhost:8761/eureka/。 ## 注2:该方式一般不适合生产,实体书里也并未提及,仅作拓展阅读。
3.简化docker-compose.yml文件
compose中所有服务共享一个隔离网络, 可使用服务名作为主机名发现其他服务
version: '3' services: discovery: image: itmuch/microservice-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 # 最简单的配置方式,等价于docker-compose.yml。
4.编排高可用的eureka server
version: "3" # 表示使用docker-compose.yml的Version 3 file format编写 services: microservice-discovery-eureka-ha1: hostname: peer1 # 指定hostname image: itmuch/microservice-discovery-eureka-ha:0.0.1-SNAPSHOT links: - microservice-discovery-eureka-ha2 ports: - "8761:8761" environment: - spring.profiles.active=peer1 microservice-discovery-eureka-ha2: hostname: peer2 image: itmuch/microservice-discovery-eureka-ha:0.0.1-SNAPSHOT links: - microservice-discovery-eureka-ha1 ports: - "8762:8762" environment: - spring.profiles.active=peer2 ## 该文件是最自然的写法,但无法正常使用。运行docker-compose up时,会报循环依赖的异常。
docker-compose up
version: "3" services: peer1: # 默认情况下,其他服务可使用服务名称连接到该服务。对于peer2节点,它需连接http://peer1:8761/eureka/,因此,我们可配置该服务的名称为peer1。 image: itmuch/microservice-discovery-eureka-ha:0.0.1-SNAPSHOT ports: - "8761:8761" environment: - spring.profiles.active=peer1 peer2: image: itmuch/microservice-discovery-eureka-ha:0.0.1-SNAPSHOT hostname: peer2 ports: - "8762:8762" environment: - spring.profiles.active=peer2 ## 使用Compose编排高可用的Eureka Server。
5.spring cloud 微服务动态伸缩
docker-compose up docker-compose scala microservice-simple-provider-user=3 microservice-gateway-zuul=3
让microservice-simple-provider-user,microservice-gateway-zuul都启动3个实例