Nacos 作为注册中心的微服务启动报错：NacosException: failed to req API:/nacos/v1/ns/instance after all servers([http

1. 问题描述

最近在尝试使用 Spring Cloud Alibaba 的 Nacos 作为注册中心搭建微服务环境时，微服务启动发生错误，报错如下：

2020-11-16 16:34:40.633 ERROR 10640 --- [           main] c.a.c.n.registry.NacosServiceRegistry    : nacos registry, product-service(172.20.139.51:9002) register failed...NacosRegistration{nacosDiscoveryProperties=NacosDiscoveryProperties{serverAddr='http://127.0.0.1:8848', endpoint='', namespace='', watchDelay=30000, logName='', service='product-service(172.20.139.51:9002)', weight=1.0, clusterName='DEFAULT', group='DEFAULT_GROUP', namingLoadCacheAtStart='false', metadata={preserved.register.source=SPRING_CLOUD}, registerEnabled=true, ip='172.20.139.51', networkInter, port=9002, secure=false, accessKey='', secretKey='', heartBeatInterval=null, heartBeatTimeout=null, ipDeleteTimeout=null}},

com.alibaba.nacos.api.exception.NacosException: failed to req API:/nacos/v1/ns/instance after all servers([http://127.0.0.1:8848]) tried: ErrCode:400, ErrMsg:caused: dom name can only have these characters: 0-9a-zA-Z-._:, current: DEFAULT_GROUP@@product-service(172.20.139.51:9002);
	at com.alibaba.nacos.client.naming.net.NamingProxy.reqApi(NamingProxy.java:552) ~[nacos-client-1.3.3.jar:na]
	at com.alibaba.nacos.client.naming.net.NamingProxy.reqApi(NamingProxy.java:491) ~[nacos-client-1.3.3.jar:na]
	at com.alibaba.nacos.client.naming.net.NamingProxy.reqApi(NamingProxy.java:486) ~[nacos-client-1.3.3.jar:na]
	at com.alibaba.nacos.client.naming.net.NamingProxy.registerService(NamingProxy.java:239) ~[nacos-client-1.3.3.jar:na]
	at com.alibaba.nacos.client.naming.NacosNamingService.registerInstance(NacosNamingService.java:200) ~[nacos-client-1.3.3.jar:na]
	at com.alibaba.cloud.nacos.registry.NacosServiceRegistry.register(NacosServiceRegistry.java:70) ~[spring-cloud-starter-alibaba-nacos-discovery-2.2.3.RELEASE.jar:2.2.3.RELEASE]
	at org.springframework.cloud.client.serviceregistry.AbstractAutoServiceRegistration.register(AbstractAutoServiceRegistration.java:239) [spring-cloud-commons-2.2.5.RELEASE.jar:2.2.5.RELEASE]
	at com.alibaba.cloud.nacos.registry.NacosAutoServiceRegistration.register(NacosAutoServiceRegistration.java:78) [spring-cloud-starter-alibaba-nacos-discovery-2.2.3.RELEASE.jar:2.2.3.RELEASE]
	at org.springframework.cloud.client.serviceregistry.AbstractAutoServiceRegistration.start(AbstractAutoServiceRegistration.java:138) [spring-cloud-commons-2.2.5.RELEASE.jar:2.2.5.RELEASE]
	at org.springframework.cloud.client.serviceregistry.AbstractAutoServiceRegistration.bind(AbstractAutoServiceRegistration.java:101) [spring-cloud-commons-2.2.5.RELEASE.jar:2.2.5.RELEASE]
	at org.springframework.cloud.client.serviceregistry.AbstractAutoServiceRegistration.onApplicationEvent(AbstractAutoServiceRegistration.java:88) [spring-cloud-commons-2.2.5.RELEASE.jar:2.2.5.RELEASE]
	at org.springframework.cloud.client.serviceregistry.AbstractAutoServiceRegistration.onApplicationEvent(AbstractAutoServiceRegistration.java:47) [spring-cloud-commons-2.2.5.RELEASE.jar:2.2.5.RELEASE]
	at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172) [spring-context-5.2.8.RELEASE.jar:5.2.8.RELEASE]
	at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165) [spring-context-5.2.8.RELEASE.jar:5.2.8.RELEASE]
	at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139) [spring-context-5.2.8.RELEASE.jar:5.2.8.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:404) [spring-context-5.2.8.RELEASE.jar:5.2.8.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:361) [spring-context-5.2.8.RELEASE.jar:5.2.8.RELEASE]
	at org.springframework.boot.web.servlet.context.WebServerStartStopLifecycle.start(WebServerStartStopLifecycle.java:46) [spring-boot-2.3.3.RELEASE.jar:2.3.3.RELEASE]
	at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:182) [spring-context-5.2.8.RELEASE.jar:5.2.8.RELEASE]
	at org.springframework.context.support.DefaultLifecycleProcessor.access$200(DefaultLifecycleProcessor.java:53) [spring-context-5.2.8.RELEASE.jar:5.2.8.RELEASE]
	at org.springframework.context.support.DefaultLifecycleProcessor$LifecycleGroup.start(DefaultLifecycleProcessor.java:360) [spring-context-5.2.8.RELEASE.jar:5.2.8.RELEASE]
	at org.springframework.context.support.DefaultLifecycleProcessor.startBeans(DefaultLifecycleProcessor.java:158) [spring-context-5.2.8.RELEASE.jar:5.2.8.RELEASE]
	at org.springframework.context.support.DefaultLifecycleProcessor.onRefresh(DefaultLifecycleProcessor.java:122) [spring-context-5.2.8.RELEASE.jar:5.2.8.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:895) [spring-context-5.2.8.RELEASE.jar:5.2.8.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:554) [spring-context-5.2.8.RELEASE.jar:5.2.8.RELEASE]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:143) [spring-boot-2.3.3.RELEASE.jar:2.3.3.RELEASE]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:758) [spring-boot-2.3.3.RELEASE.jar:2.3.3.RELEASE]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:750) [spring-boot-2.3.3.RELEASE.jar:2.3.3.RELEASE]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) [spring-boot-2.3.3.RELEASE.jar:2.3.3.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) [spring-boot-2.3.3.RELEASE.jar:2.3.3.RELEASE]
	at org.springframework.boot.builder.SpringApplicationBuilder.run(SpringApplicationBuilder.java:140) [spring-boot-2.3.3.RELEASE.jar:2.3.3.RELEASE]
	at com.experience.product.ProductApplication.main(ProductApplication.java:22) [classes/:na]
           

Spring Cloud 以及 Spring Boot 版本如下：

...
<parent>
    <artifactId>spring-boot-parent</artifactId>
    <groupId>org.springframework.boot</groupId>
    <version>2.3.3.RELEASE</version>
</parent>

...

<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-alibaba-dependencies</artifactId>
    <version>2.2.3.RELEASE</version>
    <type>pom</type>
    <scope>import</scope>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-dependencies</artifactId>
    <version>Hoxton.SR8</version>
    <type>pom</type>
    <scope>import</scope>
</dependency>
           

application.yml 配置如下：

server:
  port: 9002
spring:
  application:
    name: product-service
  cloud:
    nacos:
      discovery:
        server-addr: http://127.0.0.1:8848/
        service: ${spring.application.name}(${spring.cloud.client.ip-address}:${server.port})
           

2. 问题原因

异常日志中关键信息在于：ErrMsg:caused: dom name can only have these characters: 0-9a-zA-Z-._: 配置文件中，配置服务名 spring.cloud.nacos.discovery.service 为  ${spring.application.name}(${spring.cloud.client.ip-address}:${server.port}) 时，出现了“(”和“)”，而该配置只支持 0-9a-zA-Z-._: 的字符，这个在 eureka 中是没有这个限制的。

3. 解决方法

将配置文件改成如下：

server:
  port: 9002
spring:
  application:
    name: product-service
  cloud:
    nacos:
      discovery:
        server-addr: http://127.0.0.1:8848/
        service: ${spring.application.name}-${spring.cloud.client.ip-address}:${server.port}