Eureka集群
Eureka集群搭建
Eureka集群解决的问题:
eureka的作用是注册中心 ,所有生产端的服务都会在注册中心进行注册,如果说注册中心发生了宕机、网络闪断,那么消费者就不能在注册中心找到服务进行消费
搭建Eureka集群,如果注册中心a发生宕机,会自动将a的信息同步到b/c。。。。。
第一种方式
我们再新建两个module
microservice-eureka-server-2002 microservice-eureka-server-2003
pom.xml
<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>com.li</groupId>
<artifactId>springcloud01</artifactId>
<version>1.0-SNAPSHOT</version>
</parent>
<artifactId>microservice-eureka-server-2002</artifactId>
<properties>
<java.version>1.8</java.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-test</artifactId>
<scope>test</scope>
</dependency>
<!-- 修改后立即生效,热部署 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>springloaded</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
在2002 2003的主启动类加上@EnableEurekaServer
前面单机的时候 eureka注册中心实例名称 是localhost,现在是集群,不能三个实例都是localhost,这里复杂的办法是搞三个虚拟机,麻烦,这里有简单办法,直接配置本机hosts,来实现本机域名映射;
找到 C:\Windows\System32\drivers\etc 打开hosts,加配置
然后修改三个项目的application.yml文件,主要是修改 hostname和defaultZone,
2001修改:
server:
port: 2001
context-path: /
eureka:
instance:
hostname: eureka2001.lcl.com
client:
register-with-eureka: false
fetch-registry: false
service-url:
defaultZone: http://eureka2002.lcl.com:2002/eureka/,http://eureka2003.lcl.com:2003/eureka/
2002修改:
server:
port: 2002
context-path: /
eureka:
instance:
hostname: eureka2002.lcl.com
client:
register-with-eureka: false
fetch-registry: false
service-url:
defaultZone: http://eureka2001.lcl.com:2001/eureka/,http://eureka2003.lcl.com:2003/eureka/
2003修改:
server:
port: 2003
context-path: /
eureka:
instance:
hostname: eureka2003.lcl.com
client:
register-with-eureka: false
fetch-registry: false
service-url:
defaultZone: http://eureka2001.lcl.com:2001/eureka/,http://eureka2002.lcl.com:2002/eureka/
修改服务提供者项目的application.yml,主要修改eureka.client.service-url.defaultZone
server:
port: 1001
context-path: /
spring:
datasource:
type: com.alibaba.druid.pool.DruidDataSource
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/xm?useUnicode=true&characterEncoding=utf8
username: root
password: 123
jpa:
hibernate:
ddl-auto: update
show-sql: true
eureka:
instance:
hostname: localhost #eureka客户端主机实例名称
appname: microservice-student #客户端服务名
instance-id: microservice-student:1001 #客户端实例名称
prefer-ip-address: true #显示IP
client:
service-url:
defaultZone: http://eureka2001.lcl.com:2001/eureka/,http://eureka2002.lcl.com:2002/eureka/,http://eureka2003.lcl.com:2003/eureka/ #把服务注册到eureka注册中心
info:
groupId: com.li.springcloud01
artifactId: microservice-student-provider-1001
version: 1.0-SNAPSHOT
userName: http://javaxl.com
phone: 123456
然后在地址栏输入你在本地还有配置文件配置的域名就能访问了
第二种方式
第一种的3个模块除了yml文件不同,其他的都是一样,所以我们可以把它整合到一个模块中去,全部集成到application.yml中就可以,然后我们在IDEA的启动配置中分别读取这个配置文件不同的端口
新建一个模块 microservice-eureka-server
添加配置:
pom.xml
<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>com.li</groupId>
<artifactId>springcloud01</artifactId>
<version>1.0-SNAPSHOT</version>
</parent>
<artifactId>microservice-eureka-server</artifactId>
<properties>
<java.version>1.8</java.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-test</artifactId>
<scope>test</scope>
</dependency>
<!-- 修改后立即生效,热部署 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>springloaded</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
application.yml
---
server:
port: 2001
context-path: /
eureka:
instance:
hostname: eureka2001.lcl.com
client:
register-with-eureka: false
fetch-registry: false
service-url:
defaultZone: http://eureka2002.lcl.com:2002/eureka/,http://eureka2003.lcl.com:2003/eureka/
spring:
profiles: eureka2001
---
server:
port: 2002
context-path: /
eureka:
instance:
hostname: eureka2002.lcl.com
client:
register-with-eureka: false
fetch-registry: false
service-url:
defaultZone: http://eureka2001.lcl.com:2001/eureka/,http://eureka2003.lcl.com:2003/eureka/
spring:
profiles: eureka2002
---
server:
port: 2003
context-path: /
eureka:
instance:
hostname: eureka2003.lcl.com
client:
register-with-eureka: false
fetch-registry: false
service-url:
defaultZone: http://eureka2001.lcl.com:2001/eureka/,http://eureka2002.lcl.com:2002/eureka/
spring:
profiles: eureka2003
---
把这个模块复制3份,读取不同的配置即可
然后在这个模块的启动类加上@EnableEurekaServer
一样也能访问我们的集群了
自我保护机制
开发环境,我们经常会遇到上面这个红色的警告;
当我们长时间为访问服务以及变更服务实例名称的时候,就会出现这个红色警告;
默认情况,如果服务注册中心再一段时间内没有接收到某个微服务实例的心跳,服务注册中心会注销该实例(默认90秒)。
由于正式环境,经常会有网络故障,网络延迟问题发生,服务和注册中心无法正常通信,此时服务是正常的,不应该注销该服务,Eureka这时候,就通过“自我保护模式”来解决问题,当短时间和服务失去通信时,保留服务信息,当恢复网络和通信时候,退出“自我保护模式”;
通过“自我保护模式”,使Eureka集群更加的健壮和稳定;