SpringCloud 服务注册与发现之Zookeeper

cheese

发布于 2023-10-25 11:16:56

1670

发布于 2023-10-25 11:16:56

文章被收录于专栏：Java PorterJava Porter

大纲

背景引入 : Eureka2.0宣布停止更新

SpringCloud 整合Zookeeper替代Eureka

Zookeeper是什么?
zookeeper是一个分布式协调工具，可以实现注册中心功能

环境要求
- Centos 7.x
- 配置好网络,可以ping通网络
- 关闭防火墙 systemctl stop firewalled
关闭Linux服务器防火墙后启动zookeeper服务器
zookeeper服务器取代Eureka服务器，zk作为服务注册中心

模拟实现

Zookeeper环境搭建

打开虚拟机

使用ssh远程连接到服务器主机
- 校验主机环境

进入zookpeer,bin路径运行 zkServer.sh

运行 zkClient.sh
- ./zkCli.sh无需添加start ,(Server端需要)

此处可以看到成功进入zookeeper后会有welcome提示,与监听端口提示
同时进入内置命令行系统

补充 : zookeeper客户端常用命令

启动客户端：./zkCli.sh -server ip:port（如果连接本地Zookeeper，那么ip:port可省略）。
退出客户端：quit。
查看指定节点子节点信息：ls 节点，比如查看根节点下子节点信息（新安装的Zookeeper根节点就一个zookeeper节点）
创建节点：create 父节点path/子节点 [子节点数据]，父节点path不能为空，可以是/或其他path（默认情况下创建的是持久化的节点，既不是顺序也不是临时的）。
获取节点数据：get 节点path，如果节点没有信息，返回null。
修改节点数据：set 节点path 节点数据。
删除节点：delete 节点path。
删除某个包含子节点的节点：deleteall 节点path（正常情况下，如果某个节点下有子节点，delete是不能删除的）。
帮助：help，通过它可以查看zookeeper命令详情。

Zookeeper数据结构

Zookeeper是一个树形目录服务，具有树形的结构层次，每个节点称为ZNode，每个节点会存储数据（少量数据1M）和节点信息。

节点分类

PERSISTENT：持久化节点，即使Zookeeper服务关闭，节点信息也不会丢失。
EPHEMERAL：临时节点，可以理解为客户端会话期间存储的节点信息，-e。
PERSISTENT_SEQUENTIAL：持久化顺序节点，持久化节点基础上，节点的存储是有顺序的，-s。
EPHEMERAL_SEQUENTIAL：临时顺序节点，临时节点基础上，节点的存储是有顺序的，-es。

服务提供者Payment8004

环境搭建
- pom文件

<?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>cloud2023</artifactId>
        <groupId>top.ljzstudy.springcloud</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>cloud-provider-payment8004</artifactId>

    <dependencies>
        <!-- SpringBoot整合Web组件 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency><!-- 引入自己定义的api通用包，可以使用Payment支付Entity -->
            <groupId>top.ljzstudy.springcloud</groupId>
            <artifactId>cloud-api-commons</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
        <!-- SpringBoot整合zookeeper客户端 -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-zookeeper-discovery</artifactId>
            <!--先排除自带的zookeeper3.5.3-->
            <exclusions>
                <exclusion>
                    <groupId>org.apache.zookeeper</groupId>
                    <artifactId>zookeeper</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <!--添加zookeeper3.5.8版本-->
        <dependency>
            <groupId>org.apache.zookeeper</groupId>
            <artifactId>zookeeper</artifactId>
            <version>3.5.8</version>
        </dependency>
        <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>

</project>

编写application.yaml文件

#8004表示注册到zookeeper服务器的支付服务提供者端口号
server:
  port: 8004
#服务别名----注册zookeeper到注册中心名称
spring:
  application:
    name: cloud-provider-payment
  cloud:
    zookeeper:
      connect-string: 192.168.10.100:2181 #配置上文连接的开启Zookeeper Server的虚拟机ip与port

编写主启动类

package top.ljzstudy.springcloud;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

@SpringBootApplication
@EnableDiscoveryClient //该注解用于向使用consul或者zookeeper作为注册中心时注册服务
public class PaymentMain8004 {
    public static void main(String[] args) {
        SpringApplication.run(PaymentMain8004.class,args);
    }
}

编写控制层

package top.ljzstudy.springcloud.controller;

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.UUID;

@RestController
@Slf4j
public class PaymentController {
    @Value("${server.port}")
    private String serverPort;

    @RequestMapping(value = "/payment/zk")
    public String paymentzk() {
        return "springcloud with zookeeper: " + serverPort + "\t" + UUID.randomUUID().toString();
    }
}

运行Payment8004,同时查看zookeeper节点变化

访问 : http://localhost:8004/payment/zk

GET http://localhost:8004/payment/zk

HTTP/1.1 200 
Content-Type: text/plain;charset=UTF-8
Content-Length: 69
Date: Sat, 09 Sep 2023 02:06:08 GMT
Keep-Alive: timeout=60
Connection: keep-alive

springcloud with zookeeper: 8004	0bd73366-4e5f-4573-97e6-bcd4d697741a

Response code: 200; Time: 265ms; Content length: 69 bytes

获取格式化json传

{
  "name": "cloud-provider-payment",
  "id": "8e1412bd-e8ee-41bf-80be-d5e20d072a90",
  "address": "DESKTOP-C0R184F",
  "port": 8004,
  "sslPort": null,
  "payload": {
    "@class": "org.springframework.cloud.zookeeper.discovery.ZookeeperInstance",
    "id": "application-1",
    "name": "cloud-provider-payment",
    "metadata": {}
  },
  "registrationTimeUTC": 1694224727460,
  "serviceType": "DYNAMIC",
  "uriSpec": {
    "parts": [
      {
        "value": "scheme",
        "variable": true
      },
      {
        "value": "://",
        "variable": false
      },
      {
        "value": "address",
        "variable": true
      },
      {
        "value": ":",
        "variable": false
      },
      {
        "value": "port",
        "variable": true
      }
    ]
  }
}

服务节点是临时节点还是持久节点?
测试,
- 先关闭payment8004服务,然后查看zookeeper节点,这次启动服务观察两次节点的变化

现象
- 当第一次Payment8004关闭时zookeeper服务端立即将cloud-provider-payment节点剔除
- 当Payment8004服务再次启动时访问节点数据发生变化
结论
- Zookeeper对于访问节点默认为临时节点
- Zookeeper与Eureka的机构思想不同,是CP架构,牺牲系统高可用以达到数据的强制一致性

服务消费者Consumerzk80

环境搭建
- pom文件

<?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>cloud2023</artifactId>
    <groupId>top.ljzstudy.springcloud</groupId>
    <version>1.0-SNAPSHOT</version>
  </parent>
  <modelVersion>4.0.0</modelVersion>

  <artifactId>cloud-consumerzk-order80</artifactId>

  <dependencies>
    <!-- SpringBoot整合Web组件 -->
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <!-- SpringBoot整合zookeeper客户端 -->
    <dependency>
      <groupId>org.springframework.cloud</groupId>
      <artifactId>spring-cloud-starter-zookeeper-discovery</artifactId>
      <!--先排除自带的zookeeper-->
      <exclusions>
        <exclusion>
          <groupId>org.apache.zookeeper</groupId>
          <artifactId>zookeeper</artifactId>
        </exclusion>
      </exclusions>
    </dependency>
    <!--添加zookeeper3.4.9版本-->
    <dependency>
      <groupId>org.apache.zookeeper</groupId>
      <artifactId>zookeeper</artifactId>
      <version>3.4.9</version>
    </dependency>
    <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>
</project>

编写appliaction.yaml文件

server:
  port: 80
spring:
  application:
    name: cloud-consumer-order #服务名称
  cloud:
    #注册到zookeeper地址
    zookeeper:
      connect-string: 192.168.10.100:2181

编写主启动配置

package top.ljzstudy.springcloud;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

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

编写配置类

package top.ljzstudy.springcloud.config;

import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;

@Configuration
@Slf4j
public class ApplicationContextConfig {
    @Bean
    @LoadBalanced
    public RestTemplate restTemplate(){
        return new RestTemplate();
    }
}

编写业务
- 编写控制层OrderZkController访问服务提供者Payment8004

package top.ljzstudy.springcloud.controller;

import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import javax.annotation.Resource;

@RestController
@Slf4j
public class OrderZkController {
    public static final String INVOKE_URL = "http://cloud-provider-payment";
    @Resource
    private RestTemplate restTemplate;

    @GetMapping(value = "/consumer/payment/zk")
    public String paymentInfo(){
        return restTemplate.getForObject(INVOKE_URL+"/payment/zk",String.class);
    }

}

测试
- 启动Consumerzk80服务

访问http://localhost:80/consumer/payment/zk

GET http://localhost:80/consumer/payment/zk

HTTP/1.1 200 
Content-Type: text/plain;charset=UTF-8
Content-Length: 69
Date: Sat, 09 Sep 2023 03:18:21 GMT
Keep-Alive: timeout=60
Connection: keep-alive

springcloud with zookeeper: 8004	02b8c343-f953-4219-93bc-94015a9a4fee

Response code: 200; Time: 1932ms; Content length: 69 bytes

观察zookeeper客户端节点变化

{
  "name": "cloud-consumer-order",
  "id": "48442b14-1d74-43b2-8eb7-b719d62ca07b",
  "address": "DESKTOP-C0R184F",
  "port": 80,
  "sslPort": null,
  "payload": {
    "@class": "org.springframework.cloud.zookeeper.discovery.ZookeeperInstance",
    "id": "application-1",
    "name": "cloud-consumer-order",
    "metadata": {}
  },
  "registrationTimeUTC": 1694229466011,
  "serviceType": "DYNAMIC",
  "uriSpec": {
    "parts": [
      {
        "value": "scheme",
        "variable": true
      },
      {
        "value": "://",
        "variable": false
      },
      {
        "value": "address",
        "variable": true
      },
      {
        "value": ":",
        "variable": false
      },
      {
        "value": "port",
        "variable": true
      }
    ]
  }
}

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原始发表：2023-10-24，如有侵权请联系 cloudcommunity@tencent.com 删除

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