Example code cloud address

https://gitee.com/zhang-xin-1/springcloud1

 

1, Create Eureka project module

Create eureka project

  Create a spring Lnitializr project

Direct search import Eureka dependency  

 

Configuration dependency 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>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.2.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>cn.tedu</groupId>
    <artifactId>sp05-eureka</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>sp05-eureka</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Hoxton.SR12</spring-cloud.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</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>

Configure application.yml

spring:
  application:
    name: eureka-server
# 8001  8101  8201
# 2001  3001  4001  5001  6001
server:
  port: 2001
eureka:
  server:
    # Disable self-protection mode
    enable-self-preservation: false
  instance:
    # host name
    hostname: eureka1
  client:
    # For a single server, do not register with yourself or pull from yourself
    register-with-eureka: false
    fetch-registry: false

  Detailed explanation of eureka configuration file

eureka cluster servers are distinguished by hostname

eureka.server.enable-self-preservation

eureka's self-protection status: does the rate of heartbeat failure exceed 85% within 15 minutes? If it exceeds, Eureka Server will protect the current instance registration information and prompt a warning. Once in the protection mode, Eureka Server will try to protect the information in its service registry and will not delete the data in the service registry. That is, no micro services will be logged off

eureka.client.register-with-eureka=false

Do not register with yourself

eureka.client.fetch-registry=false

Do not pull registration information from itself

eureka.instance.lease-expiration-duration-in-seconds

After the last heartbeat, how long is the interval between determining that the microservice is unavailable? 90 by default

  Add notes to the main program

add to  @ EnableEurekaServer

package cn.tedu.sp05;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@EnableEurekaServer
@SpringBootApplication
public class Sp05EurekaApplication {

	public static void main(String[] args) {
		SpringApplication.run(Sp05EurekaApplication.class, args);
	}

}

Modify the hosts file and add eureka domain name mapping

hosts file address:

C:\Windows\System32\drivers\etc\hosts

127.0.0.1       eureka1
127.0.0.1       eureka2

Start and access the test  

• http://eureka1:2001

2, service provider (service registration eureka client)  

Modify the item service, user service and order service to register the microservice with the eureka server

pom.xml add eureka dependency (add)

<dependency>
	<groupId>org.springframework.cloud</groupId>
	<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>

application.yml add eureka registration configuration (add)

eureka:
  client:
    service-url:
      defaultZone: http://eureka1:2001/eureka

eureka.instance.lease-renewal-interval-in-seconds
Heartbeat interval, 30 seconds by default

defaultZone, the default location, can be modified to a specific geographic location, such as beiJing, shangHai, shenZhen, etc. it indicates the deployment location of eureka server, which needs to be provided by ECs

eureka.client.registry-fetch-interval-seconds
The interval between pulling registration information is 30 seconds by default

The main program enables the service registration discovery client (@ EnableDiscoveryClient)

Modify item service, user service and order service,
Main program addition  @ EnableDiscoveryClient   annotation

package cn.tedu.sp05;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@EnableEurekaServer
@SpringBootApplication
public class Sp05EurekaApplication {

    public static void main(String[] args) {
        SpringApplication.run(Sp05EurekaApplication.class, args);
    }

}

  Start and visit eureka to view the registration information

• http://eureka1:2001

3, High availability of Eureka and service providers  

Item service high availability

startup parameter  -- server.port   You can override the port configuration in yml

Configure startup parameters

--server.port=8001 

 

  Start another port service

Copy springboot project

--server.port=8002

 

  Start test

Visit eureka to view the item service registration information

  Access two port tests

http://localhost:8001/35
http://localhost:8002/35

  eureka high availability (profile Profile knowledge points)

Add profile profiles for both servers

  application-eureka1.yml(profile configuration file naming format application-xxxxx.yml)

# application-eureka1.yml
eureka:
  instance:
    # host name
    hostname: eureka1
  client:
    # Cluster servers register and pull each other
    register-with-eureka: true
    fetch-registry: true
    service-url:
      defaultZone: http://eureka2:2002/eureka

application-eureka2.yml

# application-eureka2.yml
eureka:
  instance:
    # host name
    hostname: eureka2
  client:
    # Cluster servers register and pull each other
    register-with-eureka: true
    fetch-registry: true
    service-url:
      defaultZone: http://eureka1:2001/eureka

  Configure startup parameters  -- spring.profiles.active   and  -- server.port

eureka1 startup parameters:

--spring.profiles.active=eureka1 --server.port=2001

eureka2 startup parameters:

 

 

  If running on the command line, you can add parameters to the command line:

java -jar xxx.jar --spring.profiles.active=eureka1 --server.port=2001 

  Visit the eureka server to view the registration information

 http://eureka1:2001/

http://eureka2:2002/

 

  When the eureka client registers, it registers with two servers

 

Modify the following microservices

sp02-itemservice

sp03-userservice

sp04-orderservice

eureka:
  client:
    service-url:
      defaultZone: http://eureka1:2001/eureka, http://eureka2:2002/eureka

When one eureka service goes down, another eureka service can still be connected