Spring Cloud Gateway异常：No servers available for service: ms-authentication-server

问题场景 #

本地运行微服务集群时，通过Spring Cloud Gateway访问ms-authentication-server服务时触发报错：No servers available for service: ms-authentication-server。直接访问该服务的URL可正常响应，将网关路由的uri从负载均衡格式lb://ms-authentication-server改为具体的http://localhost:...后也能正常工作，但负载均衡方式访问始终失败。Eureka控制台未显示相关错误信息。

相关配置信息 #

网关服务器配置 #

pom.xml

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-webflux</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-gateway</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        <version>4.1.0</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>       
</dependencies>

application.yml

server:
  port: 8085
spring:
  application:
    name: ms-gateway-server
  cloud:
    gateway:
      routes:
        - id: ms-authentication-server
          uri: lb://ms-authentication-server
          predicates:
            - Path=/api/v1/**
          filters:
            - StripPrefix=2
    loadbalancer:
      ribbon:
        enabled: false

eureka:
  client:
    registerWithEureka: true
    fetchRegistry: false
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/
  instance:
    preferIpAddress: true
    leaseRenewalIntervalInSeconds: 10
    leaseExpirationDurationInSeconds: 30

Eureka服务器pom.xml配置 #

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>3.2.1</version>
    <relativePath/>
</parent>
<groupId>com.cristhianvg</groupId>
<artifactId>eureka-server</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>eureka-server</name>
<description>Demo project for Spring Boot</description>
<properties>
    <java.version>17</java.version>
    <spring-cloud.version>2023.0.0</spring-cloud.version>
</properties>
<dependencies>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        <version>4.1.0</version>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>
<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-dependencies</artifactId>
            <version>${spring-cloud.version}</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

使用版本 #

• Spring Boot 3.2.1
• Spring Cloud 4.1.0 (2023.0.0)

修复方案 #

问题核心原因是目标微服务ms-authentication-server配置了独立的上下文路径，导致网关通过负载均衡标识访问时，无法正确匹配服务的实际路径。调整该微服务的上下文路径配置即可解决问题，具体可选择两种方式：

1. 移除目标服务的上下文路径配置（如删除server.servlet.context-path或server.web.context-path配置项）；
2. 保留上下文路径的同时，修改网关路由的uri为lb://ms-authentication-server/[上下文路径]，并同步调整StripPrefix等过滤器参数适配路径规则。

内容的提问来源于stack exchange，提问作者Cristhian Villegas García