title: Tracing with Jaeger doesn't work with docker-compose
body: <p>I instrumented a simple Spring-Boot application with Jaeger, but when I run the application within a Docker container with docker-compose, I can't see any traces in the Jaeger frontend.</p>
  
  <p>I'm creating the tracer configuration by reading the properties from environment variables that I set in the docker-compose file.</p>
  
  <p>This is how I create the tracer:</p>
  
  <pre><code>Configuration config = Configuration.fromEnv();
  return config.getTracer();
  </code></pre>
  
  <p>And this is my docker-compose file:</p>
  
  <pre><code>version: '2'
  
  services:
      demo:
              build: opentracing_demo/.
              ports: 
                      - "8080:8080"
              environment: 
                      - JAEGER_SERVICE_NAME=hello_service
                      - JAEGER_AGENT_HOST=jaeger
                      - JAEGER_AGENT_PORT=6831
      jaeger: 
              image: jaegertracing/all-in-one:latest
              ports:
                      - "5775:5775/udp"
                      - "6831:6831/udp"
                      - "6832:6832/udp"
                      - "5778:5778"
                      - "16686:16686"
                      - "14268:14268"
                      - "9411:9411"
  </code></pre>
  
  <p>You can also find my project on <a href="https://github.com/TheManawaha/opentracing_demo" rel="noreferrer">GitHub</a>.</p>
  
  <p>What am I doing wrong?</p>