Using Apache Skywalking (Incubator) for Distributed Tracing

Introduction to Apache Skywalking (Incubator)

Apache Skywalking (Incubator) is an APM system designed for microservice architecture and cloud-native architecture systems that supports distributed tracing. Apache Skywalking (Incubator) collects application call chain information by loading probes and analyzes the collected call chain information to generate relationships and service metrics between applications and services. Currently, Apache Skywalking (Incubating) supports multiple languages, including Java, .Net Core, Node.js, and Go.

Skywalking currently supports dissecting the operation of distributed systems from six visualization dimensions. The overview view provides a global view of applications and components, including the number of components and applications, alarm fluctuations, slow service lists, and application throughput; the topology map shows the entire application’s topology based on application dependencies; the application view shows upstream and downstream relationships, TopN services, JVM-related information, and corresponding host information from the perspective of a single application. The service view focuses on the operating status of a single service entry and its upstream and downstream dependencies, helping users optimize and monitor individual services; the call chain shows all points of interest along with the execution duration of each point for a single request; the alarm view provides real-time alerts for applications, servers, and services based on configured thresholds.

Dubbo and Apache Skywalking (Incubator)

Writing Dubbo Sample Program

The Dubbo sample program has been uploaded to the Github repository for your convenience.

API Project

Service interface:

package org.apache.skywalking.demo.interfaces;

public interface HelloService {
	String sayHello(String name);
}

Dubbo Service Provider Project

package org.apache.skywalking.demo.provider;

@Service(version = "${demo.service.version}",
	application = "${dubbo.application.id}",
	protocol = "${dubbo.protocol.id}",
	registry = "${dubbo.registry.id}", timeout = 60000)
public class HelloServiceImpl implements HelloService {

	public String sayHello(String name) {
		LockSupport.parkNanos(TimeUnit.SECONDS.toNanos(1));
		return "Hello, " + name;
	}

}

Consumer Project

package org.apache.skywalking.demo.consumer;

@RestController
public class ConsumerController {

	private static int COUNT = 0;

	@Reference(version = "${demo.service.version}",
		application = "${dubbo.application.id}",
		url = "dubbo://localhost:20880", timeout = 60000)
	private HelloService helloService;

	@GetMapping("/sayHello/{name}")
	public String sayHello(@PathVariable(name = "name") String name) {
		if ((COUNT++) % 3 == 0){
			throw new RuntimeException();
		}
		LockSupport.parkNanos(TimeUnit.SECONDS.toNanos(2));
		return helloService.sayHello(name);
	}
}

Deploying Apache Skywalking (Incubator)

Apache Skywalking (Incubator) provides two deployment modes: single-node mode and cluster mode. Below are the deployment steps for single-node mode; for details on cluster mode, refer to the documentation.

Dependencies on Third-Party Components

1. JDK8+
2. Elasticsearch 5.x

Deployment Steps

1. Download Apache Skywalking Collector
2. Deploy Elasticsearch
   • Modify the elasticsearch.yml file and set cluster.name to CollectorDBCluster. This name must match the collector configuration file.
   • Modify the ES configuration network.host, changing its value to 0.0.0.0.
   • Start Elasticsearch.
3. Unzip and start the Skywalking Collector. Run the bin/startup.sh command to start the Skywalking Collector.

Start Sample Program

Before starting the sample program, execute the compile and package command:

./mvnw clean package

Start Service Provider

java -jar -javaagent:$AGENT_PATH/skywalking-agent.jar -Dskywalking.agent.application_code=dubbo-provider -Dskywalking.collector.servers=localhost:10800 dubbo-provider/target/dubbo-provider.jar

Start Service Consumer

java -jar -javaagent:$AGENT_PATH/skywalking-agent.jar -Dskywalking.agent.application_code=dubbo-consumer -Dskywalking.collector.servers=localhost:10800 dubbo-consumer/target/dubbo-consumer.jar 

Access the Service Provided by Consumer

curl http://localhost:8080/sayHello/test

Skywalking Monitoring Screenshots:

Home

Topology Map

Application View

JVM Information

Service View

Service Consumer:

Service Provider:

Trace View

Span Information:

Alarm View

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