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Zipkin works well locally but not in docker container. All the microservices are registered well in the Eureka and they can communicate well. But the only problem is Zipkin. I am getting the following error:

org.springframework.web.client.ResourceAccessException: I/O error on
POST request for "http://localhost:9411/api/v2/spans": Connect to
http://localhost:9411 [localhost/127.0.0.1] failed: Connection refused

my docker-compose.yaml is as follows:

version: '3.8'

services:
  currency-exchange:
    image: samankt/springboot-udemy-currency-exchange:0.0.1-SNAPSHOT
    mem_limit: 512m
    ports:
      - '8000:8000'
    networks:
      - saman-network  
    environment:
      EUREKA.CLIENT.SERVICE-URL.DEFAULTZONE: http://naming-server:8761/eureka
      EUREKA.INSTANCE.PREFERIPADDRESS: true  
      SPRING.ZIPKIN.BASE-URL: http://zipkin-server:9411/
      RABBIT_URI: amqp://guest:guest@rabbitmq:5672
      SPRING_RABBITMQ_HOST: rabbitmq
      SPRING_ZIPKIN_SENDER_TYPE: rabbit
    depends_on:
      - naming-server
      - rabbitmq
      
  api-gateway:
    image: samankt/springboot-udemy-currency-api-gateway:0.0.1-snapshot
    mem_limit: 512m
    ports:
      - '8765:8765'
    networks:
      - saman-network  
    environment:
      EUREKA.CLIENT.SERVICE-URL.DEFAULTZONE: http://naming-server:8761/eureka
      EUREKA.INSTANCE.PREFERIPADDRESS: true  
      SPRING.ZIPKIN.BASE-URL: http://zipkin-server:9411/
      RABBIT_URI: amqp://guest:guest@rabbitmq:5672
      SPRING_RABBITMQ_HOST: rabbitmq
      SPRING_ZIPKIN_SENDER_TYPE: rabbit 
    depends_on:
      - naming-server
      - rabbitmq
      
  currency-converter:
    image: samankt/currency-conversion:0.0.1-SNAPSHOT
    mem_limit: 700m
    ports:
      - '8100:8100'
    networks:
      - saman-network  
    environment:
      EUREKA.CLIENT.SERVICE-URL.DEFAULTZONE: http://naming-server:8761/eureka
      EUREKA.INSTANCE.PREFERIPADDRESS: true  
      SPRING.ZIPKIN.BASE-URL: http://zipkin-server:9411/
      SPRING.ZIPKIN.DISCOVERYCLIENTENABLED: true 
      RABBIT_URI: amqp://guest:guest@rabbitmq:5672
      SPRING_RABBITMQ_HOST: rabbitmq
      SPRING_ZIPKIN_SENDER_TYPE: rabbit     
    depends_on:
      - naming-server
      - rabbitmq
      
  naming-server:
    image: samankt/naming-server:0.0.1-SNAPSHOT
    mem_limit: 512m
    ports:
      - '8761:8761'
    environment:
      SPRING.ZIPKIN.BASE-URL: http://zipkin-server:9411/    
    networks:
      - saman-network
      
  zipkin-server:
    image: openzipkin/zipkin:latest
    mem_limit: 400m
    ports:
      - '9411:9411'
    networks:
      - saman-network   
    environment:
      RABBIT_URI: amqp://guest:guest@rabbitmq:5672
    depends_on:
      - rabbitmq
    restart: always
      
      
  rabbitmq:
    image: rabbitmq:3.8.12-management
    ports:
      - '5672:5672'
      - '15672:15672'
    networks:
      - saman-network
    
networks: 
  saman-network:

2

Answers


  1. Chosen as BEST ANSWER

    The problem is solved when I downgraded to Spring 2.x from 3.0.

    It seems that Zipkin does not work well with Spring 3.0 currently. The problem is for docker, not local running. I could not find enough resources to support this idea. But in my experience, this is the case. I tried Zipkin with "latest" tag with Spring 3.0.0 but the problem persists. But it does work well with Spring 2.x


  2. SOLUTION 1

    The error is telling you that the connection on http://localhost:9411/api/v2/spans is refused. When you run your application inside a docker container you need to send the request not with localhost, but through the docker network (in your case saman-network). To access the docker container which runs zipkin you need to send the request to http://zipkin-server:9411/api/v2/spans.

    From Spring Boot 3 Sleuth is deprecated and you will need to use micrometer.
    To use tracing with zipkin you can add the following 4 dependencies to you pom.xml file

    <dependency>
         <groupId>io.micrometer</groupId>
         <artifactId>micrometer-tracing-bridge-brave</artifactId>
    </dependency>
    <dependency>
        <groupId>io.micrometer</groupId>
        <artifactId>micrometer-observation-test</artifactId>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>io.zipkin.reporter2</groupId>
        <artifactId>zipkin-reporter-brave</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-actuator</artifactId>
    </dependency>
    

    Finally to change the Zipkin endpoint to send the tracing information you need to add the following to your application.yaml file.

    management:
      tracing:
        sampling:
          probability: 1.0 # only for testing purpose, switch back to 0.1 for production code
      zipkin:
        tracing:
          endpoint: http://localhost:9411/api/v2/spans
    

    It is good practice to use Spring profiles, therefore you copy your
    application.yaml file and name it application-docker.yaml. In this new file you can modify the Zipkin endpoint with the zipkin container name zipkin-server.

    management:
      tracing:
        sampling:
          probability: 1.0 # only for testing purpose, switch back to 0.1 for production code
      zipkin:
        tracing:
          endpoint: http://zipkin-server:9411/api/v2/spans
    

    You can activate the Spring profiles passing SPRING_PROFILES_ACTIVATE=docker in the environment.


    SOLUTION 2

    For you this solution is faster to implement but I didn’t test it. You pass the Zipkin url as an environment value SPRING.ZIPKIN.BASE-URL inside the docker-compose.yml.
    This property was used with the Sleuth package. With Spring Boot 3 and micrometer try to pass instead: MANAGEMENT.ZIPKIN.TRACING.ENDPOINT: http://zipkin-server:9411/api/v2/spans

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