[Kubernetes] cAdvisor介绍

Posted by 胡伟煌 on 2017-08-13

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<Node_IP:port>访问。项目主页:http://github.com/google/cadvisor。

2. cAdvisor结构图

cAdvisor

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

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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:

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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

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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

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// 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

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// 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

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// 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

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// 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

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// 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
}

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