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1、Nacos brief introduction

1.1 Nacos What is it? ？

   A dynamic service discovery that is easier to build cloud native applications 、 Configuration management and service management platform .

  Nacos Service registry + A combination of configuration centers , Equivalent to $Nacos = Eureka+Config +Bus$

1.2 Nacos What can be done ？

• replace Eureka Be a service registry
• replace Config Be a service configuration center

   Project address :https://github.com/alibaba/Nacos

   Official document ：https://nacos.io/zh-cn/index.html

1.3 Various registries are more

   It is said that Nacos There are more than 10 The instance of Wan runs , It has passed the test of all kinds of large traffic such as double 11

2、 Install and run Nacos

   Prerequisite ： Local Java8+Maven The environment has been configured successfully .

   Download it from the official website first Nacos:https://github.com/alibaba/nacos/releases

   Unzip the installation package , Direct operation bin In the catalog startup.cmd

   After the command runs successfully, you can directly access http://localhost:8848/nacos, The default account passwords are nacos

3、Nacos Demonstrate as a service registry

   Official document ：https://spring-cloud-alibaba-group.github.io/github-pages/greenwich/spring-cloud-alibaba.html#_spring_cloud_alibaba_nacos_discovery

3.1 be based on Nacos Service provider

3.1.1 newly build cloudalibaba-provider-payment9001

3.1.2 pom

   Father pom

   Of this module pom:

 <dependencies>        <!--SpringCloud ailibaba nacos -->        <dependency>            <groupId>com.alibaba.cloud</groupId>            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>        </dependency>        <!-- SpringBoot Integrate Web Components  -->        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-web</artifactId>        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-actuator</artifactId>        </dependency>        <!-- Everyday use jar Package configuration -->        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-devtools</artifactId>            <scope>runtime</scope>            <optional>true</optional>        </dependency>        <dependency>            <groupId>org.projectlombok</groupId>            <artifactId>lombok</artifactId>            <optional>true</optional>        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-test</artifactId>            <scope>test</scope>        </dependency>    </dependencies>

3.1.3 yml

server:  port: 9001spring:  application:    name: nacos-payment-provider  cloud:    nacos:      discovery:        server-addr: localhost:8848 # To configure Nacos Address management:  endpoints:    web:      exposure:        include: '*'

3.1.4 Main startup class

@EnableDiscoveryClient@SpringBootApplicationpublic class PaymentMain9001{    public static void main(String[] args) {            SpringApplication.run(PaymentMain9001.class, args);    }}

3.1.5 Business class

@RestControllerpublic class PaymentController{    @Value("${server.port}")    private String serverPort;    @GetMapping(value = "/payment/nacos/{id}")    public String getPayment(@PathVariable("id") Integer id)    {        return "nacos registry, serverPort: "+ serverPort+"\t id"+id;    }}

3.1.6 test

   After starting this module, check Nacos Console

   visit ：http://localhost:9001/payment/nacos/1

   There is no problem with the test .

3.1.7 To set up cloudalibabaprovider-payment9002 modular

   In addition to the port number , Others are almost the same as cloudalibabaprovider-payment9001 Modules are consistent , The construction process is not repeated .

3.2 be based on Nacos Service consumers

3.2.1 newly build Module

   newly build cloudalibaba-consumer-nacos-order83 modular .

3.2.2 pom

 <dependencies>        <!--SpringCloud ailibaba nacos -->        <dependency>            <groupId>com.alibaba.cloud</groupId>            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>        </dependency>        <!--  Introduce your own definition of api General package , have access to Payment payment Entity -->        <dependency>            <groupId>com.atguigu.springcloud</groupId>            <artifactId>cloud-api-commons</artifactId>            <version>${project.version}</version>        </dependency>        <!-- SpringBoot Integrate Web Components  -->        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-web</artifactId>        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-actuator</artifactId>        </dependency>        <!-- Everyday use jar Package configuration -->        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-devtools</artifactId>            <scope>runtime</scope>            <optional>true</optional>        </dependency>        <dependency>            <groupId>org.projectlombok</groupId>            <artifactId>lombok</artifactId>            <optional>true</optional>        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-test</artifactId>            <scope>test</scope>        </dependency>    </dependencies>

   nacos Load balancing is supported by default , Because when we look at its dependent files, we can find , It introduces... By default Ribbon Load balancing component .

3.2.3 yml

server:  port: 83spring:  application:    name: nacos-order-consumer  cloud:    nacos:      discovery:        server-addr: localhost:8848# The name of the micro service the consumer is going to visit ( Successfully registered nacos Micro service providers of )service-url:  nacos-user-service: http://nacos-payment-provider 

3.2.4 Main startup class

@EnableDiscoveryClient@SpringBootApplicationpublic class OrderNacosMain83{    public static void main(String[] args)    {        SpringApplication.run(OrderNacosMain83.class,args);    }} 

3.2.5 Business class

OrderNacosController

@RestControllerpublic class PaymentController{    @Value("${server.port}")    private String serverPort;    @GetMapping(value = "/payment/{id}")    public String getPayment(@PathVariable("id") Integer id)    {        return "nacos registry, serverPort: "+ serverPort+"\t id"+id;    }}

ApplicationContextBean Configuration class

@Configurationpublic class ApplicationContextBean{    @Bean    @LoadBalanced    public RestTemplate getRestTemplate()    {        return new RestTemplate();    }}

3.2.6 test

After starting the service, view Nacos Console

   visit ：http://localhost:83/consumer/payment/nacos/13

   for the first time ：

   The second time ：

   Refresh a few more times to find , The service port number has been 9001 and 9002 Switch between , Because our default load balancing algorithm is the polling algorithm .

3.3 Service registry comparison

3.3.1 Nacos Ecological map

   You can see , Alibaba's ambition is still great .

3.3.2 Nacos and CAP

3.3.3 Nacos Support AP and CP Mode switching

  ==C All nodes see the same data at the same time ; and A The definition is that all requests will receive a response .==

   When to choose which mode to use ？

   Generally speaking , If the information is stored at the service level and is not required nacos-client register , And can keep the heartbeat , Then you can choose AP Pattern . Current mainstream services such as Spring cloud and Dubbo service , All apply to AP Pattern ,AP Patterns weaken consistency for the possibility of services , therefore AP Only temporary instance registration is supported in mode .

   If you need to edit or store configuration information at the service level , that CP It is necessary ,K8S Service and DNS Services apply to CP Pattern .
CP Mode, it supports the registration of persistent instances , In this case Raft The protocol is cluster operation mode , In this mode, the service must be registered before the instance is registered , If the service doesn't exist , It will return an error .

 curl -X PUT '$NACOS_SERVER:8848/nacos/v1/ns/operator/switches?entry=serverMode&value=CP'

   Here we are ,Nacos As a service registration center, I'm finished , As a configuration center, please check out the next article .