catalogue

Introduction to Eureka

Spring Cloud introduces Eureka

1. Create cloud Eureka server7001 subproject

Dependency needs to be introduced (indicates eureka server):

Write yml:

For main startup, add the annotation @EnableEurekaServer

2.The cloud-consumer-order80 of Eureka client will register into Eureka server and become a consumer of services.

1. Change POM and introduce the dependency Eureka client:

2. Change yml

3. Main startup, add @EnableEurekaClient dependency:

3.The cloud provider payment8001 of Eureka client will register into Eureka server and become a service provider.

Eureka cluster

Refer to cloud Eureka server7001 and create a new cloud Eureka server7002

Modify the hostss file:

Modify the yml of 7001 to correspond to the address of 7002:

Modify the yml of 7002 to correspond to the address of 7001:

Publish the payment service 8001 micro service to the above two Eureka cluster configurations, yml

Publish the order service 80 microservice to the above two Eureka cluster configurations.

Payment service provider 8001 cluster environment construction:

Create a new 8002 payment service.

Load balancing:

Introduction to Eureka

Service registration and service discovery: Eureka adopts the design architecture of CS. Eureka Sever is the server of service registration function, which is the service registration center. Other microservices in the system use Eureka's client to connect to Eureka Seve and maintain a heartbeat connection. In this way, the maintenance personnel of the system can monitor whether each micro service in the system is running normally through Eureka Server.
In service registration and discovery, there is a registry. When the server starts, it will register its current server information, such as service address and communication address, in the registration center by alias. The other party (consumer service provider) obtains the actual service communication address from the registry in the way of this alias, and then realizes the local RPC call. The core design idea of RPC remote call framework is to use the registry to manage a dependency between each service (service governance concept). In any RPC remote framework, there will be a registry (storing information about the service address (interface address)).

Eureka consists of two components: Eureka Server and Eureka Client
Eureka Server provides service registration service
After each micro service node is started through configuration, it will be registered in EurekaServer, so that the service registry in EurekaServer will store the information of all available service nodes, and the information of service nodes can be seen visually in the interface.
EurekaClient accesses through the registry
It is an ava client, which is used to simplify the interaction of Eureka Server. The client also has a built-in load balancer using round robin load algorithm. After the application starts, a heartbeat will be sent to Eureka Server (the default cycle is 30 seconds). If Eureka Server does not receive the heartbeat of a node in multiple heartbeat cycles, Eureka Server will remove the service node from the service registry (90 seconds by default)

Spring Cloud introduces Eureka

1. Create cloud Eureka server7001 subproject

Five steps: introduce in detail in the construction of Spring Cloud project,

Dependency needs to be introduced (indicates eureka server):

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

Write yml:

server:
  port: 7001
eureka:
  instance:
    hostname: eureka7001.com #Instance name of eureka server
  client:
    register-with-eureka: false #false means you don't register yourself
    fetch-registry: false #false indicates that you are a registry to maintain service instances
    service-url:
      defaultZone: http://eureka7002.com:7002/eureka/

For main startup, add the annotation @EnableEurekaServer

The cloud-consumer-order80 of Eureka client will register into Eureka server and become a consumer of services.

1. Change POM and introduce the dependency Eureka client:

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

2. Change yml

server:
  port: 8001
eureka:
  client:
    register-with-eureka: true
    fetch-registry: true
    service-url:
      # Cluster version
      defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka

3. Main startup, add @EnableEurekaClient dependency:

The cloud provider payment8001 of Eureka client will register into Eureka server and become a service provider.

It is consistent with the above steps.

Eureka cluster

Refer to cloud Eureka server7001 and create a new cloud Eureka server7002

Modify the hostss file:

127.0.0.1 eureka7001.com

127.0.0.1 eureka7002.com 

Fill in the hosts file, which can be opened with VSC, modified and saved.

Modify the yml of 7001 to correspond to the address of 7002:

server:
  port: 7001
spring:
  application:
    name: cloud-eureka-service
eureka:
  instance:
    # Instance name of eureka server
    hostname: eureka7001.com
  client:
    # false means that you do not register yourself with the registry
    register-with-eureka: false
    # false means that my own end is the registration center. My responsibility is to maintain service instances without retrieving services
    fetch-registry: false
    service-url:
      # Setting the address query service and registration service that interact with Eureka Server need to rely on this address
      defaultZone: http://eureka7002.com:7002/eureka/

Modify the yml of 7002 to correspond to the address of 7001:

server:
  port: 7002
spring:
  application:
    name: cloud-eureka-service2
eureka:
  instance:
    hostname:  eureka7002.com
  client:
    register-with-eureka: false
    fetch-registry: false
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka/

Publish the payment service 8001 micro service to the above two Eureka cluster configurations, yml

eureka:
  client:
    register-with-eureka: true
    fetch-registry: true
    service-url:
      # Cluster version
      defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka
 
 

Publish the order service 80 microservice to the above two Eureka cluster configurations.

eureka:
  client:
    register-with-eureka: true #Whether to put your own registration money eureka
    fetch-registry: true #Whether to retrieve the registered information from eureka
    service-url:
      # Cluster version
      defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka

Payment service provider 8001 cluster environment construction:

Previously, we built a cluster of registration centers. Similarly, we built a cluster of payment services.

Create a new 8002 payment service.

Five steps, create according to 8001.

yml:

server:
  port: 8002
spring:
  application:
    name: cloud-payment-service8002
  datasource:
    # Current data source operation type
    type: com.alibaba.druid.pool.DruidDataSource
    # mysql driver class
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/db2019?useUnicode=true&characterEncoding=UTF-8&useSSL=false&serverTimezone=GMT%2B8
    username: root
    password: root
eureka:
  client:
    register-with-eureka: true
    fetch-registry: true
    service-url:
      defaultZone: http://eureka7001.com/eureka,http://eureka7002.com/eureka

Load balancing:

Add the @LoadBalanced annotation in the config of the order service,