Kubernetes监控体系（二）之cAdvisor介绍

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 。

2. cAdvisor结构图

3. Metrics

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

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