Docker环境下Spring Boot与Elasticsearch通信失败问题排查

问题描述 #

在Docker环境中搭建Spring Boot应用与Elasticsearch通信时，遇到以下问题：

• 程序运行时抛出警告：AbstractElasticsearchRepository : Cannot create index: Connection refused; nested exception is java.lang.RuntimeException: Connection refused
• 浏览器访问http://localhost:9200/article/_search?pretty=true提示索引不存在
• 手动运行程序（非Docker容器化）时功能正常
• 已尝试调整docker-compose和Spring配置，但问题未解决

现有配置文件 #

docker-compose.yml

version: '3'

services:
  demo:
    container_name: demo
    image: demo-elastic
    build: .
    ports:
      - "8080:8080"
    depends_on:
      - es
    networks:
      - demo-network

  es:
    image: elasticsearch:7.6.2
    environment:
      - discovery.type=single-node
    ports:
      - "9200:9200"
    networks:
      - demo-network

networks:
  demo-network:
    driver: bridge

Dockerfile

# For Java 11
FROM adoptopenjdk/openjdk11:alpine-jre

ARG JAR_FILE=target/*.jar

COPY ${JAR_FILE} demo.jar

ENTRYPOINT ["java","-jar","/demo.jar"]

Config.java

@Configuration
@EnableElasticsearchRepositories(basePackages = "com.example.demo.repository")
public class Config extends AbstractElasticsearchConfiguration {

    @Value("${elasticsearch.url}")
    public String elasticsearchUrl;

    @Bean
    @Override
    public RestHighLevelClient elasticsearchClient() {
        final ClientConfiguration config = ClientConfiguration.builder()
                .connectedTo(elasticsearchUrl)
                .build();

        return RestClients.create(config).rest();
    }
}

application.properties

elasticsearch.url=localhost:9200
spring.data.elasticsearch.cluster-nodes=localhost:9200

pom.xml（核心依赖）

<dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.elasticsearch/elasticsearch -->
        <dependency>
            <groupId>org.elasticsearch</groupId>
            <artifactId>elasticsearch</artifactId>
            <version>7.6.2</version>
        </dependency>


        <!-- https://mvnrepository.com/artifact/org.elasticsearch.client/elasticsearch-rest-high-level-client -->
        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>elasticsearch-rest-high-level-client</artifactId>
            <version>7.6.2</version>
        </dependency>


        <!-- https://mvnrepository.com/artifact/org.springframework.data/spring-data-elasticsearch -->
        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-elasticsearch</artifactId>
            <version>4.0.0.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
        </dependency>

    </dependencies>

解决方案 #

1. 修正容器间通信地址 #

Docker容器内的localhost指向容器自身，而非宿主机。Spring应用容器尝试连接localhost:9200时，实际是在容器内部寻找Elasticsearch，导致连接失败。

修改application.properties，改用Docker Compose中Elasticsearch的服务名es作为主机：

elasticsearch.url=es:9200
spring.data.elasticsearch.cluster-nodes=es:9200

Docker Compose会在自定义网络demo-network中自动解析服务名到对应容器的IP，确保Spring应用能正确找到Elasticsearch容器。

2. 确保Elasticsearch完全启动 #

depends_on仅保证容器启动顺序，不确保Elasticsearch服务就绪。添加健康检查避免Spring应用在Elasticsearch未就绪时发起连接：

修改docker-compose.yml的es服务：

es:
  image: elasticsearch:7.6.2
  environment:
    - discovery.type=single-node
  ports:
    - "9200:9200"
  networks:
    - demo-network
  healthcheck:
    test: ["CMD-SHELL", "curl -s http://localhost:9200/_cluster/health | grep -q '\"status\":\"green\"'"]
    interval: 10s
    timeout: 10s
    retries: 5

修改demo服务的依赖条件：

demo:
  container_name: demo
  image: demo-elastic
  build: .
  ports:
    - "8080:8080"
  depends_on:
    es:
      condition: service_healthy
  networks:
    - demo-network

3. 统一依赖版本兼容性 #

Spring Boot 2.7.5对应的Spring Data Elasticsearch版本应为4.4.x，手动指定4.0.0.RELEASE可能导致版本不兼容。建议使用Spring Boot依赖管理自动控制版本：

修改pom.xml，替换Elasticsearch相关依赖：

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>

    <!-- 依赖Spring Boot自动管理版本 -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-elasticsearch</artifactId>
    </dependency>

    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-test</artifactId>
    </dependency>
</dependencies>

Spring Boot 2.7.5默认适配Elasticsearch 7.17.x，若继续使用7.6.2需确保版本兼容，或升级Elasticsearch容器版本到7.17.x。

4. 重新构建启动服务 #

执行以下命令更新镜像并启动容器：

docker-compose down
docker-compose build
docker-compose up -d

内容的提问来源于stack exchange，提问作者Александр Гладун