SkyWalking —— 分布式应用监控与链路追踪

SkyWalking 是一个应用性能监控系统，特别为微服务、云原生和基于容器（Docker, Kubernetes, Mesos）体系结构而设计。除了应用指标监控以外，它还能对分布式调用链路进行追踪。类似功能的组件还有：Zipkin、Pinpoint、CAT等。

上几张图，看看效果，然后再一步一步搭建并使用

1.  概念与架构

SkyWalking是一个开源监控平台，用于从服务和云原生基础设施收集、分析、聚合和可视化数据。SkyWalking提供了一种简单的方法来维护分布式系统的清晰视图，甚至可以跨云查看。它是一种现代APM，专门为云原生、基于容器的分布式系统设计。 

SkyWalking从三个维度对应用进行监视：service（服务）, service instance（实例）, endpoint（端点）

服务和实例就不多说了，端点是服务中的某个路径或者说URI

SkyWalking allows users to understand the topology relationship between Services and Endpoints, to view the metrics of every Service/Service Instance/Endpoint and to set alarm rules.

SkyWalking允许用户了解服务和端点之间的拓扑关系，查看每个服务/服务实例/端点的度量，并设置警报规则。

1.1.  架构

 

SkyWalking逻辑上分为四个部分：Probes（探针）, Platform backend（平台后端）, Storage（存储）, UI

这个结构就很清晰了，探针就是Agent负责采集数据并上报给服务端，服务端对数据进行处理和存储，UI负责展示

2.  下载与安装

SkyWalking有两中版本，ES版本和非ES版。如果我们决定采用ElasticSearch作为存储，那么就下载es版本。 

https://skywalking.apache.org/downloads/

https://archive.apache.org/dist/skywalking/

agent目录将来要拷贝到各服务所在机器上用作探针

bin目录是服务启动脚本

config目录是配置文件

oap-libs目录是oap服务运行所需的jar包

webapp目录是web服务运行所需的jar包

接下来，要选择存储了，支持的存储有：

• H2
• ElasticSearch 6, 7
• MySQL
• TiDB
• InfluxDB

作为监控系统，首先排除H2和MySQL，这里推荐InfluxDB，它本身就是时序数据库，非常适合这种场景

但是InfluxDB我不是很熟悉，所以这里先用ElasticSearch7

https://github.com/apache/skywalking/blob/master/docs/en/setup/backend/backend-storage.md

2.1.  安装ElasticSearch

https://www.elastic.co/guide/en/elasticsearch/reference/7.10/targz.html 

# 启动
./bin/elasticsearch -d -p pid
# 停止
pkill -F pid

ElasticSearch7.x需要Java 11以上的版本，但是如果你设置了环境变量JAVA_HOME的话，它会用你自己的Java版本

通常，启动过程中会报以下三个错误：

[1]: max file descriptors [4096] for elasticsearch process is too low, increase to at least [65535]
[2]: max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]
[3]: the default discovery settings are unsuitable for production use; at least one of [discovery.seed_hosts, discovery.seed_providers, cluster.initial_master_nodes] must be configured

解决方法：

在 /etc/security/limits.conf 文件中追加以下内容：

* soft nofile 65536
* hard nofile 65536
* soft nproc  4096
* hard nproc  4096

可通过以下四个命令查看修改结果：

ulimit -Hn
ulimit -Sn
ulimit -Hu
ulimit -Su

修改 /etc/sysctl.conf 文件，追加以下内容：

vm.max_map_count=262144

修改es配置文件 elasticsearch.yml 取消注释，保留一个节点

cluster.initial_master_nodes: ["node-1"]

为了能够ip:port方式访问，还需修改网络配置

network.host: 0.0.0.0

修改完是这样的：

至此，ElasticSearch算是启动成功了

接下来，在 config/application.yml 中配置es地址即可

storage:
  selector: ${SW_STORAGE:elasticsearch7}
  elasticsearch7:
    clusterNodes: ${SW_STORAGE_ES_CLUSTER_NODES:192.168.100.19:9200}

2.2.  安装Agent

https://github.com/apache/skywalking/blob/v8.2.0/docs/en/setup/service-agent/java-agent/README.md

将agent目录拷贝至各服务所在的机器上

scp -r ./agent chengjs@192.168.100.12:~/

这里，我将它拷贝至各个服务目录下

plugins是探针用到各种插件，SkyWalking插件都是即插即用的，可以把optional-plugins中的插件放到plugins中 

修改 agent/config/agent.config 配置文件，也可以通过命令行参数指定

主要是配置服务名称和后端服务地址

agent.service_name=${SW_AGENT_NAME:user-center}
collector.backend_service=${SW_AGENT_COLLECTOR_BACKEND_SERVICES:192.168.100.17:11800}

当然，也可以通过环境变量或系统属性的方式来设置，例如：

export SW_AGENT_COLLECTOR_BACKEND_SERVICES=127.0.0.1:11800

最后，在服务启动的时候用命令行参数 -javaagent 来指定探针

java -javaagent:/path/to/skywalking-agent/skywalking-agent.jar -jar yourApp.jar

例如：

java -javaagent:./agent/skywalking-agent.jar -Dspring.profiles.active=dev -Xms512m -Xmx1024m -jar demo-0.0.1-SNAPSHOT.jar

3.  启动服务

修改 webapp/webapp.yml 文件，更改端口号及后端服务地址

server:
  port: 8080

collector:
  path: /graphql
  ribbon:
    ReadTimeout: 10000
    # Point to all backend's restHost:restPort, split by ,
    listOfServers: 127.0.0.1:12800

启动服务

bin/startup.sh

或者分别依次启动

bin/oapService.sh
bin/webappService.sh

查看logs目录下的日志文件，看是否启动成功

浏览器访问 http://127.0.0.1:8080

4. 告警

 

编辑 alarm-settings.yml 设置告警规则和通知

https://github.com/apache/skywalking/blob/v8.2.0/docs/en/setup/backend/backend-alarm.md

重点说下告警通知

 

为了使用钉钉机器人通知，接下来，新建一个项目

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.4.0</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.wt.monitor</groupId>
    <artifactId>skywalking-alarm</artifactId>
    <version>1.0.0-SNAPSHOT</version>
    <name>skywalking-alarm</name>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>com.aliyun</groupId>
            <artifactId>alibaba-dingtalk-service-sdk</artifactId>
            <version>1.0.1</version>
        </dependency>

        <dependency>
            <groupId>commons-codec</groupId>
            <artifactId>commons-codec</artifactId>
            <version>1.15</version>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.75</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

可选依赖（不建议引入）

<dependency
    <groupId>org.apache.skywalking</groupId>
    <artifactId>server-core</artifactId>
    <version>8.2.0</version>
</dependency>

定义告警消息实体类

package com.wt.monitor.skywalking.alarm.domain;

import lombok.Data;

import java.io.Serializable;

/**
 * @author ChengJianSheng
 * @date 2020/12/1
 */
@Data
public class AlarmMessageDTO implements Serializable {

    private int scopeId;

    private String scope;

    /**
     * Target scope entity name
     */
    private String name;

    private String id0;

    private String id1;

    private String ruleName;

    /**
     * Alarm text message
     */
    private String alarmMessage;

    /**
     * Alarm time measured in milliseconds
     */
    private long startTime;

}

发送钉钉机器人消息

package com.wt.monitor.skywalking.alarm.service;

import com.dingtalk.api.DefaultDingTalkClient;
import com.dingtalk.api.DingTalkClient;
import com.dingtalk.api.request.OapiRobotSendRequest;
import com.taobao.api.ApiException;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.codec.binary.Base64;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;

/**
 * https://ding-doc.dingtalk.com/doc#/serverapi2/qf2nxq
 * @author ChengJianSheng
 * @data 2020/12/1
 */
@Slf4j
@Service
public class DingTalkAlarmService {

    @Value("${dingtalk.webhook}")
    private String webhook;
    @Value("${dingtalk.secret}")
    private String secret;

    public void sendMessage(String content) {
        try {
            Long timestamp = System.currentTimeMillis();
            String stringToSign = timestamp + "
" + secret;
            Mac mac = Mac.getInstance("HmacSHA256");
            mac.init(new SecretKeySpec(secret.getBytes("UTF-8"), "HmacSHA256"));
            byte[] signData = mac.doFinal(stringToSign.getBytes("UTF-8"));
            String sign = URLEncoder.encode(new String(Base64.encodeBase64(signData)),"UTF-8");

            String serverUrl = webhook + "&timestamp=" + timestamp + "&sign=" + sign;
            DingTalkClient client = new DefaultDingTalkClient(serverUrl);
            OapiRobotSendRequest request = new OapiRobotSendRequest();
            request.setMsgtype("text");
            OapiRobotSendRequest.Text text = new OapiRobotSendRequest.Text();
            text.setContent(content);
            request.setText(text);

            client.execute(request);
        } catch (ApiException e) {
            e.printStackTrace();
            log.error(e.getMessage(), e);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
            log.error(e.getMessage(), e);
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
            log.error(e.getMessage(), e);
        } catch (InvalidKeyException e) {
            e.printStackTrace();
            log.error(e.getMessage(), e);
        }
    }
}

AlarmController.java

package com.wt.monitor.skywalking.alarm.controller;

import com.alibaba.fastjson.JSON;
import com.wt.monitor.skywalking.alarm.domain.AlarmMessageDTO;
import com.wt.monitor.skywalking.alarm.service.DingTalkAlarmService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.text.MessageFormat;
import java.util.List;

/**
 * @author ChengJianSheng
 * @date 2020/12/1
 */
@Slf4j
@RestController
@RequestMapping("/skywalking")
public class AlarmController {

    @Autowired
    private DingTalkAlarmService dingTalkAlarmService;

    @PostMapping("/alarm")
    public void alarm(@RequestBody List<AlarmMessageDTO> alarmMessageDTOList) {
       log.info("收到告警信息: {}", JSON.toJSONString(alarmMessageDTOList));
       if (null != alarmMessageDTOList) {
           alarmMessageDTOList.forEach(e->dingTalkAlarmService.sendMessage(MessageFormat.format("-----来自SkyWalking的告警-----
【名称】: {0}
【消息】: {1}
", e.getName(), e.getAlarmMessage())));
       }
    }
}

5.  文档

https://skywalking.apache.org/

https://skywalking.apache.org/zh/ 

https://github.com/apache/skywalking/tree/v8.2.0/docs

https://archive.apache.org/dist/

https://www.elastic.co/guide/en/elasticsearch/reference/master/index.html