Eureka service registration and discovery

1.Eureka Basic knowledge of

1.1 What is service governance ？

1.2 What is service registration

1.3Eureka Two components

2. stand-alone Eureka Build steps

2.1 IDEA Generate eurekaServer End services registry

2.1.1 build Module cloud-eureka-server7001

2.1.2 Change POM

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>cloud2020</artifactId>
        <groupId>com.atguigu.springcloud</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>cloud-eureka-server7001</artifactId>

    <dependencies>
        <!-- https://mvnrepository.com/artifact/org.springframework.cloud/spring-cloud-starter-eureka-server -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>

        <dependency>
            <groupId>com.atguigu.springcloud</groupId>
            <artifactId>cloud-api-commons</artifactId>
            <version>${project.version}</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-web -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-web -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-devtools -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.projectlombok/lombok -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-test -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
        </dependency>

    </dependencies>
</project>

Eureka1.X and 2.X Comparative explanation of

2.1.3 Change yml

server:
  port: 7001

eureka:
  instance:
    hostname: localhost  #eureka The instance name of the server 
  client:
    register-with-eureka: false    # I don't register myself with the registry 
    fetch-registry: false   # Say you're the registry , The responsibility is to maintain service instances , There's no need to retrieve Services 
    service-url:
      defaultZone: http://${
    eureka.instance.hostname}:${
    server.port}/eureka/    # Set up with eureka server Both the interactive address query service and the registration service need to rely on this address 

2.1.4 Write the startup class

package com.atguigu.springcloud;

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

@EnableEurekaServer
@SpringBootApplication
public class EurekaMain7001 {
    
    public static void main(String[] args) {
    
        SpringApplication.run(EurekaMain7001.class,args);
    }
}

@EnableEurekaServer The annotation indicates that the service is Eureka Server node

2.1.5 test

http://localhost:7001/

2.2EurekaClient End cloud-provider-payment8001 Register into EurekaServer Become a service provider provider

2.2.1 Change pom

 <!-- https://mvnrepository.com/artifact/org.springframework.cloud/spring-cloud-starter-eureka-server -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>

1.X and 2.X Comparative explanation of ： More and more clear , Know is server End or end clinet End

2.2.2 Change yml

eureka:
  client:
    register-with-eureka: true
    fetchRegistry: true
    service-url:
      defaultZone: http://localhost:7001/eureka

2.2.3 Change startup class

Annotate the annotation in the startup class @EnableEurekaClient： Indicates that the service is Eureka Client node

2.2.4 test

Start... First server End , Then start client End
The microservice name is registered to Eureka Name
Self-protection mechanism

2.3EurekaClient End cloud-consumer-order80 Register into EurekaServer Become a service consumer consumer

The changes are similar to 2.2, Change yml Change the name of the microservice to ：cloud-order-service, Others are the same .

3. colony Eureka Build steps

3.1Eureka Explanation of cluster principle

terms of settlement ： build Eureka Registry cluster , Load balancing + Fault tolerance

3.2EurekaServer Cluster environment construction steps

3.2.1 newly build cloud-eureka-server7002

Reference resources cloud-eureka-server7001, Change POM

3.2.2 Modify the mapping configuration

find C:\Windows\System32\drivers\etc The next path hosts file , Add the following

127.0.0.1 eureka7001.com
127.0.0.1 eureka7002.com

3.2.3 Write YML

Register with each other , Watch each other

7001

server:
  port: 7001

eureka:
  instance:
    hostname: eureka7001.com    #eureka The instance name of the server 
  client:
    register-with-eureka: false    # I don't register myself with the registry 
    fetch-registry: false   # Say you're the registry , The responsibility is to maintain service instances , There's no need to retrieve Services 
    service-url:
      defaultZone: http://eureka7002.com:7002/eureka/    # Set up with eureka server Both the interactive address query service and the registration service need to rely on this address 

7002

server:
  port: 7002

eureka:
  instance:
    hostname: eureka7002.com #eureka The instance name of the server 
  client:
    register-with-eureka: false    # I don't register myself with the registry 
    fetch-registry: false   # Say you're the registry , The responsibility is to maintain service instances , There's no need to retrieve Services 
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka/     # Set up with eureka server Both the interactive address query service and the registration service need to rely on this address 

3.2.4 Main start

Main start ( Copy cloud-eureka-server7001 Main startup class to 7002 that will do )

3.2.5 Separately 80 and 8001 Sign up to Eureka colony

80 and 8001 Of yml I just need to change it defaultZone that will do .

service-url:
  defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka  # Cluster version 

3.2.6 test

Start... First 7001 and 7002 form Eureka colony , Then start the provider 8001, Finally, start the consumer 80

3.2.7 Payment service providers 8001 Cluster environment construction

newly build cloud-provider-payment8002, Reference resources cloud-provider-payment8001

Change POM, Change yml, Changing the slogan , modify contoller, Bring the port number when returning , Convenient test

3.2.8 Load balancing

The order service access address cannot be written dead , Change to http://CLOUD-PAYMENT-SERVICE. That is, register to eureka The address of the provider in

Use @LoadBalanced Note given RestTemplate The ability to load balance

3.2.9 The test again

Find out 8002 Error report in execution , No corresponding mapper,8002 Of mapper The binding is 8001 Of dao, Names cause conflicts , Change 8002 by PaymentDao1, test OK

4.actuator The micro service information is perfect

4.1 Host name ： Service name modification

instance:
    instance-id: payment8001

4.2 The access information is ip message

prefer-ip-address: true

introduce actuatorjar Package can be displayed ip Information

5. Service discovery Discovery

5.1 For registering into eureka The micro service inside , Information about the service can be obtained through service discovery

modify cloud-provider-payment8001 Of Controller

@Resource
private DiscoveryClient discoveryClient;
 
@GetMapping(value = "/payment/discovery")
public Object discovery(){
    
    List<String> services = discoveryClient.getServices();
    for (String element : services) {
    
        log.info("***** element:"+element);
    }
    List<ServiceInstance> instances = discoveryClient.getInstances("CLOUD-PAYMENT-SERVICE");
    for (ServiceInstance instance : instances) {
    
        log.info(instance.getServiceId()+"\t"+instance.getHost()+"\t"+instance.getPort()+"\t"+instance.getUri());
    }
    return this.discoveryClient;
}

5.2 Start class

8001 Annotate the main startup class ： @EnableDiscoveryClient

5.3 Self testing

Start first EurekaServer,7001/7002 service , Restart 8001 Main startup class , It's going to take a moment

http://localhost:8001/payment/discovery

6.Eureka Self protection

6.1 The fault phenomenon

6.2 The cause of the problem

In a word ： At some point, a microservice is unavailable ,Eureka It won't clean up immediately , The information of the micro service will still be saved . Belong to CAP Inside AP Branch

6.3 How to prohibit self-protection （ Self protection is not prohibited in general production environments , Turn off the development environment to facilitate debugging ）

6.3.1 Registry Center eureakeServer End 7001

Factory default , The self-protection mechanism is open

eureka.server.enable-self-preservation = true

Use eureka.server.enable-self-preservation = false You can disable self-protection mode

server:
  enable-self-preservation: false
  eviction-interval-timer-in-ms: 2000

stay eurekaServer End 7001 Turn off the self-protection mechanism

6.3.2 Producer client eureakeClient End 8001

instance:
    lease-renewal-interval-in-seconds:  1
   lease-expiration-duration-in-seconds:  2

The default configuration ：eureka.instance.lease-renewal-interval-in-seconds=30
eureka.instance.lease-expiration-duration-in-seconds=90

test ：

7001 and 8001 All configured , Start... First 7001 Restart 8001, Shut down first 8001, It was deleted immediately .