Java Distributed Tracing (Jaeger, Zipkin)

Distributed Tracing is a technique used to monitor and troubleshoot complex, distributed systems by tracking requests as they propagate through various services. For Java applications, tools like Jaeger and Zipkin are commonly used for distributed tracing. Below is a comprehensive guide to implementing distributed tracing in Java applications using Jaeger and Zipkin.

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Key Concepts of Distributed Tracing

1. Trace: A record of the entire request path through the system.
2. Span: A single operation within a trace, representing a unit of work.
3. Context Propagation: Passing trace context between services to maintain the trace.
4. Instrumentation: Adding tracing code to the application.

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1. Jaeger

Overview

• Description: An open-source, end-to-end distributed tracing system.
• Features: High scalability, support for multiple languages, and integration with OpenTracing.

Setting Up Jaeger

1. Install Jaeger:

• Docker: Run Jaeger using Docker.
  bash docker run -d --name jaeger \ -e COLLECTOR_ZIPKIN_HTTP_PORT=9411 \ -p 5775:5775/udp \ -p 6831:6831/udp \ -p 6832:6832/udp \ -p 5778:5778 \ -p 16686:16686 \ -p 14268:14268 \ -p 9411:9411 \ jaegertracing/all-in-one:1.30

1. Add Dependencies:
   Add the following dependencies to your pom.xml for a Maven project.

   <dependency>
       <groupId>io.jaegertracing</groupId>
       <artifactId>jaeger-client</artifactId>
       <version>1.6.0</version>
   </dependency>
   <dependency>
       <groupId>io.opentracing.contrib</groupId>
       <artifactId>opentracing-spring-jaeger-cloud-starter</artifactId>
       <version>3.2.0</version>
   </dependency>

3. Configure Jaeger:
   Add the following configuration to your application.properties or application.yml.

   opentracing.jaeger.udp-sender.host=localhost
   opentracing.jaeger.udp-sender.port=6831
   opentracing.jaeger.log-spans=true

4. Instrument Your Application:
   Use the @Traced annotation to trace methods.

   import io.opentracing.Tracer;
   import io.opentracing.contrib.spring.web.client.TracingRestTemplateInterceptor;
   import org.springframework.context.annotation.Bean;
   import org.springframework.context.annotation.Configuration;
   import org.springframework.web.client.RestTemplate;

   @Configuration
   public class TracingConfig {

       @Bean
       public RestTemplate restTemplate(Tracer tracer) {
           RestTemplate restTemplate = new RestTemplate();
           restTemplate.getInterceptors().add(new TracingRestTemplateInterceptor(tracer));
           return restTemplate;
       }
   }

5. View Traces:
   Open a browser and navigate to http://localhost:16686 to view traces in the Jaeger UI.

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2. Zipkin

Overview

• Description: A distributed tracing system that helps gather timing data needed to troubleshoot latency problems.
• Features: Supports multiple storage backends, easy integration with Spring Boot.

Setting Up Zipkin

1. Install Zipkin:

• Docker: Run Zipkin using Docker.
  bash docker run -d -p 9411:9411 openzipkin/zipkin

1. Add Dependencies:
   Add the following dependencies to your pom.xml for a Maven project.

   <dependency>
       <groupId>org.springframework.cloud</groupId>
       <artifactId>spring-cloud-starter-zipkin</artifactId>
       <version>2.2.8.RELEASE</version>
   </dependency>

3. Configure Zipkin:
   Add the following configuration to your application.properties or application.yml.

   spring.zipkin.base-url=http://localhost:9411
   spring.sleuth.sampler.probability=1.0

4. Instrument Your Application:
   Use the @NewSpan annotation to trace methods.

   import org.springframework.cloud.sleuth.annotation.NewSpan;
   import org.springframework.stereotype.Service;

   @Service
   public class MyService {

       @NewSpan("my-span")
       public void myMethod() {
           // method logic
       }
   }

5. View Traces:
   Open a browser and navigate to http://localhost:9411 to view traces in the Zipkin UI.

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Best Practices

1. Consistent Sampling: Use consistent sampling to ensure traces are collected for all related requests.
2. Context Propagation: Ensure trace context is propagated across all services.
3. Instrument Key Components: Focus on instrumenting key components like HTTP clients, databases, and message queues.
4. Monitor and Alert: Set up monitoring and alerts for trace data to detect issues early.

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Resources

• Official Documentation: Jaeger, Zipkin
• Tutorials and Examples: Jaeger Tutorial, Zipkin Tutorial

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