Why Does spring.config.import Not Override Environment Variables in a Spring Boot 3 Microservice?

I have a project with the following microservices:

• FE: Spring Boot 3 application that displays information to the user
• BE: Spring Boot 3 application that connects to the database and sends information to FE
• MySql: Database storing data
• Config Server: Spring Cloud application storing service configurations on Github

In both FE and BE services, I configured the property spring.config.import to connect with the Config Server. For example, in the BE project (springcloud-fe-thymeleaf-be-springboot-db-sql-mysql-config_BE) the application.properties file is as follows:

PROPERTIESCopied
# Port
server.port=8081

# Service Name
spring.application.name=be

# Config Server
spring.config.import=configserver:http://localhost:8888

I attempted to override this property using the docker-compose.yaml file by setting spring.config.import: configserver:http://config:8888:

YAMLCopied
be:
    image: be-image:0.0.1
    container_name: be-container
    build:
      context: ./springcloud-fe-thymeleaf-be-springboot-db-sql-mysql-config_BE
      dockerfile: Dockerfile
    depends_on:
      config:
        condition: service_healthy
    ports:
      - 8081:8081
    environment:
      spring.config.import: configserver:http://config:8888
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:8081/actuator/health"]
      interval: 10s
      timeout: 10s
      retries: 5
      start_period: 10s
    networks:
      - helloworld-network

I run the setup with the command:

BASHCopied
docker-compose up -d --build

The following error appears in Docker Desktop:

PLAINTEXTCopied
2025-01-20 17:02:36 Caused by: org.springframework.web.client.ResourceAccessException: I/O error on GET request for "http://localhost:8888/be/default": Connection refused
2025-01-20 17:02:36     at org.springframework.web.client.RestTemplate.createResourceAccessException(RestTemplate.java:926)
2025-01-20 17:02:36     at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:906)

It seems that the BE service is still connecting to localhost instead of the intended config service. This issue also occurs in the FE service and when using Docker and Kubernetes environment variables.

Tested on:

• Java: 23
• Spring Boot: 3.4.1
• Spring Cloud: 2024.0.0
• Maven: 3.9.6

Repository: https://github.com/wisniewskikr/chrisblog-it-cloud/tree/main/spring-cloud/config/springcloud-fe-thymeleaf-be-springboot-db-sql-mysql-config

Why is the spring.config.import property not being overwritten by environment variables from Docker, Docker Compose, or Kubernetes?