Kubernetes监控体系（二）之cAdvisor介绍

Bertha 。 2022-06-08 00:56 324阅读 0赞

> 本文个人博客地址：[http://www.huweihuang.com/article/kubernetes/monitoring/cadvisor-introduction/][http_www.huweihuang.com_article_kubernetes_monitoring_cadvisor-introduction]

## 1. cAdvisor简介 ##

cAdvisor对Node机器上的资源及容器进行实时监控和性能数据采集，包括CPU使用情况、内存使用情况、网络吞吐量及文件系统使用情况，cAdvisor集成在Kubelet中，当kubelet启动时会自动启动cAdvisor，即一个cAdvisor仅对一台Node机器进行监控。kubelet的启动参数–cadvisor-port可以定义cAdvisor对外提供服务的端口，默认为4194。可以通过浏览器访问。项目主页：[http://github.com/google/cadvisor][http_github.com_google_cadvisor] 。

## 2. cAdvisor结构图 ##

![这里写图片描述][SouthEast]

## 3. Metrics ##

<table> 
 <thead> 
  <tr> 
   <th>分类</th> 
   <th>字段</th> 
   <th>描述</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>cpu</td> 
   <td>cpu_usage_total</td> 
   <td></td> 
  </tr> 
  <tr> 
   <td></td> 
   <td>cpu_usage_system</td> 
   <td></td> 
  </tr> 
  <tr> 
   <td></td> 
   <td>cpu_usage_user</td> 
   <td></td> 
  </tr> 
  <tr> 
   <td></td> 
   <td>cpu_usage_per_cpu</td> 
   <td></td> 
  </tr> 
  <tr> 
   <td></td> 
   <td>load_average</td> 
   <td>Smoothed average of number of runnable threads x 1000</td> 
  </tr> 
  <tr> 
   <td>memory</td> 
   <td>memory_usage</td> 
   <td>Memory Usage</td> 
  </tr> 
  <tr> 
   <td></td> 
   <td>memory_working_set</td> 
   <td>Working set size</td> 
  </tr> 
  <tr> 
   <td>network</td> 
   <td>rx_bytes</td> 
   <td>Cumulative count of bytes received</td> 
  </tr> 
  <tr> 
   <td></td> 
   <td>rx_errors</td> 
   <td>Cumulative count of receive errors encountered</td> 
  </tr> 
  <tr> 
   <td></td> 
   <td>tx_bytes</td> 
   <td>Cumulative count of bytes transmitted</td> 
  </tr> 
  <tr> 
   <td></td> 
   <td>tx_errors</td> 
   <td>Cumulative count of transmit errors encountered</td> 
  </tr> 
  <tr> 
   <td>filesystem</td> 
   <td>fs_device</td> 
   <td>Filesystem device</td> 
  </tr> 
  <tr> 
   <td></td> 
   <td>fs_limit</td> 
   <td>Filesystem limit</td> 
  </tr> 
  <tr> 
   <td></td> 
   <td>fs_usage</td> 
   <td>Filesystem usage</td> 
  </tr> 
 </tbody> 
</table>

## 4. cAdvisor源码 ##

### 4.1. cAdvisor入口函数 ###

**cadvisor.go**

func main() {
        defer glog.Flush()
        flag.Parse()
        if *versionFlag {
            fmt.Printf("cAdvisor version %s (%s)\n", version.Info["version"], version.Info["revision"])
            os.Exit(0)
        }
        setMaxProcs()
        memoryStorage, err := NewMemoryStorage()
        if err != nil {
            glog.Fatalf("Failed to initialize storage driver: %s", err)
        }
        sysFs, err := sysfs.NewRealSysFs()
        if err != nil {
            glog.Fatalf("Failed to create a system interface: %s", err)
        }
        collectorHttpClient := createCollectorHttpClient(*collectorCert, *collectorKey)
        containerManager, err := manager.New(memoryStorage, sysFs, *maxHousekeepingInterval, *allowDynamicHousekeeping, ignoreMetrics.MetricSet, &collectorHttpClient)
        if err != nil {
            glog.Fatalf("Failed to create a Container Manager: %s", err)
        }
        mux := http.NewServeMux()
        if *enableProfiling {
            mux.HandleFunc("/debug/pprof/", pprof.Index)
            mux.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
            mux.HandleFunc("/debug/pprof/profile", pprof.Profile)
            mux.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
        }
        // Register all HTTP handlers.
        err = cadvisorhttp.RegisterHandlers(mux, containerManager, *httpAuthFile, *httpAuthRealm, *httpDigestFile, *httpDigestRealm)
        if err != nil {
            glog.Fatalf("Failed to register HTTP handlers: %v", err)
        }
        cadvisorhttp.RegisterPrometheusHandler(mux, containerManager, *prometheusEndpoint, nil)
        // Start the manager.
        if err := containerManager.Start(); err != nil {
            glog.Fatalf("Failed to start container manager: %v", err)
        }
        // Install signal handler.
        installSignalHandler(containerManager)
        glog.Infof("Starting cAdvisor version: %s-%s on port %d", version.Info["version"], version.Info["revision"], *argPort)
        addr := fmt.Sprintf("%s:%d", *argIp, *argPort)
        glog.Fatal(http.ListenAndServe(addr, mux))
    }

核心代码：

memoryStorage, err := NewMemoryStorage()
    sysFs, err := sysfs.NewRealSysFs()
    #创建containerManager
    containerManager, err := manager.New(memoryStorage, sysFs, *maxHousekeepingInterval, *allowDynamicHousekeeping, ignoreMetrics.MetricSet, &collectorHttpClient)
    #启动containerManager
    err := containerManager.Start()

### 4.2. cAdvisor Client的使用 ###

import "github.com/google/cadvisor/client"
    func main(){
        client, err := client.NewClient("http://192.168.19.30:4194/")   //http://<host-ip>:<port>/
    }

#### 4.2.1 client定义 ####

**cadvisor/client/client.go**

// Client represents the base URL for a cAdvisor client.
    type Client struct {
        baseUrl string
    }
    // NewClient returns a new v1.3 client with the specified base URL.
    func NewClient(url string) (*Client, error) {
        if !strings.HasSuffix(url, "/") {
            url += "/"
        }
        return &Client{
            baseUrl: fmt.Sprintf("%sapi/v1.3/", url),
        }, nil
    }

#### 4.2.2. client方法 ####

**1）MachineInfo**

// MachineInfo returns the JSON machine information for this client.
    // A non-nil error result indicates a problem with obtaining
    // the JSON machine information data.
    func (self *Client) MachineInfo() (minfo *v1.MachineInfo, err error) {
           u := self.machineInfoUrl()
           ret := new(v1.MachineInfo)
           if err = self.httpGetJsonData(ret, nil, u, "machine info"); err != nil {
                  return
           }
           minfo = ret
           return
    }

**2）ContainerInfo**

// ContainerInfo returns the JSON container information for the specified
    // container and request.
    func (self *Client) ContainerInfo(name string, query *v1.ContainerInfoRequest) (cinfo *v1.ContainerInfo, err error) {
           u := self.containerInfoUrl(name)
           ret := new(v1.ContainerInfo)
           if err = self.httpGetJsonData(ret, query, u, fmt.Sprintf("container info for %q", name)); err != nil {
                  return
           }
           cinfo = ret
           return
    }

**3）DockerContainer**

// Returns the JSON container information for the specified
    // Docker container and request.
    func (self *Client) DockerContainer(name string, query *v1.ContainerInfoRequest) (cinfo v1.ContainerInfo, err error) {
           u := self.dockerInfoUrl(name)
           ret := make(map[string]v1.ContainerInfo)
           if err = self.httpGetJsonData(&ret, query, u, fmt.Sprintf("Docker container info for %q", name)); err != nil {
                  return
           }
           if len(ret) != 1 {
                  err = fmt.Errorf("expected to only receive 1 Docker container: %+v", ret)
                  return
           }
           for _, cont := range ret {
                  cinfo = cont
           }
           return
    }

**4）AllDockerContainers**

// Returns the JSON container information for all Docker containers.
    func (self *Client) AllDockerContainers(query *v1.ContainerInfoRequest) (cinfo []v1.ContainerInfo, err error) {
           u := self.dockerInfoUrl("/")
           ret := make(map[string]v1.ContainerInfo)
           if err = self.httpGetJsonData(&ret, query, u, "all Docker containers info"); err != nil {
                  return
           }
           cinfo = make([]v1.ContainerInfo, 0, len(ret))
           for _, cont := range ret {
                  cinfo = append(cinfo, cont)
           }
           return
    }

文章参考：[http://blog.opskumu.com/cadvisor.html][http_blog.opskumu.com_cadvisor.html]

[http_www.huweihuang.com_article_kubernetes_monitoring_cadvisor-introduction]: http://www.huweihuang.com/article/kubernetes/monitoring/cadvisor-introduction/
[http_github.com_google_cadvisor]: http://github.com/google/cadvisor
[SouthEast]: /images/20220608/e876edb4723b49ba9ef7dbccbba0d9fb.png
[http_blog.opskumu.com_cadvisor.html]: http://blog.opskumu.com/cadvisor.html