kubectl源码分析之top pod

淡淡的烟草味﹌ 2023-02-16 06:57 6阅读 0赞

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目前刚开始写一个月，一共写了18篇原创文章，文章目录如下：

[istio多集群探秘，部署了50次多集群后我得出的结论][istio_50]

[istio多集群链路追踪，附实操视频][istio]

[istio防故障利器，你知道几个,istio新手不要读，太难！][istio_istio]

[istio业务权限控制，原来可以这么玩][istio 1]

[istio实现非侵入压缩，微服务之间如何实现压缩][istio 2]

[不懂envoyfilter也敢说精通istio系列-http-rbac-不要只会用AuthorizationPolicy配置权限][envoyfilter_istio_-http-rbac-_AuthorizationPolicy]

[不懂envoyfilter也敢说精通istio系列-02-http-corsFilter-不要只会vs][envoyfilter_istio_-02-http-corsFilter-_vs]

[不懂envoyfilter也敢说精通istio系列-03-http-csrf filter-再也不用再代码里写csrf逻辑了][envoyfilter_istio_-03-http-csrf filter-_csrf]

[不懂envoyfilter也敢说精通istio系列http-jwt\_authn-不要只会RequestAuthorization][envoyfilter_istio_http-jwt_authn-_RequestAuthorization]

[不懂envoyfilter也敢说精通istio系列-05-fault-filter-故障注入不止是vs][envoyfilter_istio_-05-fault-filter-_vs]

[不懂envoyfilter也敢说精通istio系列-06-http-match-配置路由不只是vs][envoyfilter_istio_-06-http-match-_vs]

[不懂envoyfilter也敢说精通istio系列-07-负载均衡配置不止是dr][envoyfilter_istio_-07-_dr]

[不懂envoyfilter也敢说精通istio系列-08-连接池和断路器][envoyfilter_istio_-08-]

[不懂envoyfilter也敢说精通istio系列-09-http-route filter][envoyfilter_istio_-09-http-route filter]

[不懂envoyfilter也敢说精通istio系列-network filter-redis proxy][envoyfilter_istio_-network filter-redis proxy]

[不懂envoyfilter也敢说精通istio系列-network filter-HttpConnectionManager][envoyfilter_istio_-network filter-HttpConnectionManager]

[不懂envoyfilter也敢说精通istio系列-ratelimit-istio ratelimit完全手册][envoyfilter_istio_-ratelimit-istio ratelimit]

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type TopPodOptions struct {//top pod结构体
    	ResourceName    string
    	Namespace       string
    	Selector        string
    	SortBy          string
    	AllNamespaces   bool
    	PrintContainers bool
    	NoHeaders       bool
    	PodClient       corev1client.PodsGetter
    	HeapsterOptions HeapsterTopOptions
    	Client          *metricsutil.HeapsterMetricsClient
    	Printer         *metricsutil.TopCmdPrinter
    	DiscoveryClient discovery.DiscoveryInterface
    	MetricsClient   metricsclientset.Interface
    
    	genericclioptions.IOStreams
    }

//创建top pod命令
    func NewCmdTopPod(f cmdutil.Factory, o *TopPodOptions, streams genericclioptions.IOStreams) *cobra.Command {
    	if o == nil {
    		o = &TopPodOptions{//初始化结构体
    			IOStreams: streams,
    		}
    	}
    
    	cmd := &cobra.Command{//创建cobra命令
    		Use:                   "pod [NAME | -l label]",
    		DisableFlagsInUseLine: true,
    		Short:                 i18n.T("Display Resource (CPU/Memory/Storage) usage of pods"),
    		Long:                  topPodLong,
    		Example:               topPodExample,
    		Run: func(cmd *cobra.Command, args []string) {
    			cmdutil.CheckErr(o.Complete(f, cmd, args))//准备
    			cmdutil.CheckErr(o.Validate())//校验
    			cmdutil.CheckErr(o.RunTopPod())//运行
    		},
    		Aliases: []string{"pods", "po"},//别名
    	}
    	cmd.Flags().StringVarP(&o.Selector, "selector", "l", o.Selector, "Selector (label query) to filter on, supports '=', '==', and '!='.(e.g. -l key1=value1,key2=value2)")//selector选项
    	cmd.Flags().StringVar(&o.SortBy, "sort-by", o.Selector, "If non-empty, sort pods list using specified field. The field can be either 'cpu' or 'memory'.")//sort-by选项
    	cmd.Flags().BoolVar(&o.PrintContainers, "containers", o.PrintContainers, "If present, print usage of containers within a pod.")//containers选项
    	cmd.Flags().BoolVarP(&o.AllNamespaces, "all-namespaces", "A", o.AllNamespaces, "If present, list the requested object(s) across all namespaces. Namespace in current context is ignored even if specified with --namespace.")//所有名称空间选项
    	cmd.Flags().BoolVar(&o.NoHeaders, "no-headers", o.NoHeaders, "If present, print output without headers.")//no-headers选项
    	o.HeapsterOptions.Bind(cmd.Flags())//绑定heapster选项
    	return cmd
    }

//准备函数
    func (o *TopPodOptions) Complete(f cmdutil.Factory, cmd *cobra.Command, args []string) error {
    	var err error
    	if len(args) == 1 {//如果参数是1个，则把参数赋值给资源
    		o.ResourceName = args[0]
    	} else if len(args) > 1 {//参数大于1个报错
    		return cmdutil.UsageErrorf(cmd, "%s", cmd.Use)
    	}
    
    	o.Namespace, _, err = f.ToRawKubeConfigLoader().Namespace()//设置namespace
    	if err != nil {
    		return err
    	}
    	clientset, err := f.KubernetesClientSet()//获取clientset
    	if err != nil {
    		return err
    	}
    
    	o.DiscoveryClient = clientset.DiscoveryClient//从clientset获取discoveryClient
    	config, err := f.ToRESTConfig()//获取restconfig
    	if err != nil {
    		return err
    	}
    	o.MetricsClient, err = metricsclientset.NewForConfig(config)//通过restConfig获取MetrixClient
    	if err != nil {
    		return err
    	}
    
    	o.PodClient = clientset.CoreV1()//通过clientset获取PodClient
    	o.Client = metricsutil.NewHeapsterMetricsClient(clientset.CoreV1(), o.HeapsterOptions.Namespace, o.HeapsterOptions.Scheme, o.HeapsterOptions.Service, o.HeapsterOptions.Port)//设置heapersterclient
    
    	o.Printer = metricsutil.NewTopCmdPrinter(o.Out)//设置打印对象
    	return nil
    }
    
    
    //校验
    func (o *TopPodOptions) Validate() error {
    	if len(o.SortBy) > 0 {//如果sort-by有值，则值必须为memory或cpu
    		if o.SortBy != sortByCPU && o.SortBy != sortByMemory {
    			return errors.New("--sort-by accepts only cpu or memory")
    		}
    	}
    	if len(o.ResourceName) > 0 && len(o.Selector) > 0 {//资源名称和selector不能同时指定
    		return errors.New("only one of NAME or --selector can be provided")
    	}
    	return nil
    }

//运行
    func (o TopPodOptions) RunTopPod() error {
    	var err error
    	selector := labels.Everything()//设置标签选择器为所有
    	if len(o.Selector) > 0 {//如果--selector不为空，设置标签选择器为解析后的值
    		selector, err = labels.Parse(o.Selector)
    		if err != nil {
    			return err
    		}
    	}
    
    	apiGroups, err := o.DiscoveryClient.ServerGroups()//从discoveryClient获取apiGroup
    	if err != nil {
    		return err
    	}
    
    	metricsAPIAvailable := SupportedMetricsAPIVersionAvailable(apiGroups)//判断metrics是否支持apiGroup
    
    	metrics := &metricsapi.PodMetricsList{}//创建PodMetricsList对象
    	if metricsAPIAvailable {//如果metrics支持apiGroup
    		metrics, err = getMetricsFromMetricsAPI(o.MetricsClient, o.Namespace, o.ResourceName, o.AllNamespaces, selector)//获取metrics
    		if err != nil {
    			return err
    		}
    	} else {
    		metrics, err = o.Client.GetPodMetrics(o.Namespace, o.ResourceName, o.AllNamespaces, selector)//通过client获取metrics
    		if err != nil {
    			return err
    		}
    	}
    
    	// TODO: Refactor this once Heapster becomes the API server.
    	// First we check why no metrics have been received.
    	if len(metrics.Items) == 0 {//如果metrics为空
    		// If the API server query is successful but all the pods are newly created,
    		// the metrics are probably not ready yet, so we return the error here in the first place.
    		e := verifyEmptyMetrics(o, selector)//验证空metrics
    		if e != nil {
    			return e
    		}
    	}
    	if err != nil {
    		return err
    	}
    
    	return o.Printer.PrintPodMetrics(metrics.Items, o.PrintContainers, o.AllNamespaces, o.NoHeaders, o.SortBy)//打印metrics
    }

//通过metrics api获取metrics
    func getMetricsFromMetricsAPI(metricsClient metricsclientset.Interface, namespace, resourceName string, allNamespaces bool, selector labels.Selector) (*metricsapi.PodMetricsList, error) {
    	var err error
    	ns := metav1.NamespaceAll//名称空间为所有
    	if !allNamespaces {//如果没有指定all-namespaces，名称空间为特定值
    		ns = namespace
    	}
    	versionedMetrics := &metricsv1beta1api.PodMetricsList{}//构造PodMetricsList对象
    	if resourceName != "" {//如果资源名称不为空
    		m, err := metricsClient.MetricsV1beta1().PodMetricses(ns).Get(resourceName, metav1.GetOptions{})//获取指定资源名称的metrics
    		if err != nil {
    			return nil, err
    		}
    		versionedMetrics.Items = []metricsv1beta1api.PodMetrics{*m}//包装
    	} else {
    		versionedMetrics, err = metricsClient.MetricsV1beta1().PodMetricses(ns).List(metav1.ListOptions{LabelSelector: selector.String()})//通过labelselector获取metrics
    		if err != nil {
    			return nil, err
    		}
    	}
    	metrics := &metricsapi.PodMetricsList{}//构造podMetricsList对象
    	err = metricsv1beta1api.Convert_v1beta1_PodMetricsList_To_metrics_PodMetricsList(versionedMetrics, metrics, nil)//把metrics转为PodMetricsList
    	if err != nil {
    		return nil, err
    	}
    	return metrics, nil//返回结果
    }

//验证空metrics
    func verifyEmptyMetrics(o TopPodOptions, selector labels.Selector) error {
    	if len(o.ResourceName) > 0 {//如果资源名称不控
    		pod, err := o.PodClient.Pods(o.Namespace).Get(o.ResourceName, metav1.GetOptions{})//获取pod
    		if err != nil {
    			return err
    		}
    		if err := checkPodAge(pod); err != nil {//检查年龄
    			return err
    		}
    	} else {
    		pods, err := o.PodClient.Pods(o.Namespace).List(metav1.ListOptions{//获取符合selector的所有pod
    			LabelSelector: selector.String(),
    		})
    		if err != nil {
    			return err
    		}
    		if len(pods.Items) == 0 {
    			return nil
    		}
    		for _, pod := range pods.Items {//遍历pods检查年龄
    			if err := checkPodAge(&pod); err != nil {
    				return err
    			}
    		}
    	}
    	return errors.New("metrics not available yet")
    }
    
    func checkPodAge(pod *v1.Pod) error {
    	age := time.Since(pod.CreationTimestamp.Time)//获取pod从创建到现在的时间
    	if age > metricsCreationDelay {//如果pod存在时间大于特定时间
    		message := fmt.Sprintf("Metrics not available for pod %s/%s, age: %s", pod.Namespace, pod.Name, age.String())
    		klog.Warningf(message)//输出klog警告
    		return errors.New(message)//返回错误
    	} else {
    		klog.V(2).Infof("Metrics not yet available for pod %s/%s, age: %s", pod.Namespace, pod.Name, age.String())//输出info
    		return nil//返回nil
    	}
    }

// 打印pod metrics
    func (printer *TopCmdPrinter) PrintPodMetrics(metrics []metricsapi.PodMetrics, printContainers bool, withNamespace bool, noHeaders bool, sortBy string) error {
    	if len(metrics) == 0 {//如果metrics为空返回
    		return nil
    	}
    	w := printers.GetNewTabWriter(printer.out)//把out包装为tabWriter
    	defer w.Flush()//defer flush
    	if !noHeaders {//如果没有指定noHeaders
    		if withNamespace {//如果withnamespace
    			printValue(w, NamespaceColumn)//打印namespace列
    		}
    		if printContainers {//如果打印容器为真
    			printValue(w, PodColumn)//打印pod列
    		}
    		printColumnNames(w, PodColumns)//打印其他列
    	}
    
    	p, err := NewPodMetricsSorter(metrics, printContainers, withNamespace, sortBy)//排序器
    	if err != nil {
    		return err
    	}
    	sort.Sort(p)//执行排序
    
    	for _, m := range metrics {// 遍历metrics
    		err := printSinglePodMetrics(w, &m, printContainers, withNamespace)//打印单行
    		if err != nil {
    			return err
    		}
    	}
    	return nil
    }

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[istio_50]: https://mp.weixin.qq.com/s/_OPMjmWCDSTlmbAxytg33A
[istio]: https://mp.weixin.qq.com/s/kjvtno_UzJAGr1joxm3tvw
[istio_istio]: https://mp.weixin.qq.com/s/e2-p_NY31Mc5y07S4Bb1JQ
[istio 1]: https://mp.weixin.qq.com/s/iTV0SCQLhSOTYncp3PxoHQ
[istio 2]: https://mp.weixin.qq.com/s/eINlrT242RlAwfuZu1_PcA
[envoyfilter_istio_-http-rbac-_AuthorizationPolicy]: https://mp.weixin.qq.com/s/Q-yTGBNqkjOov49LTXPrPA
[envoyfilter_istio_-02-http-corsFilter-_vs]: https://mp.weixin.qq.com/s/bFMdrT7OKSqoWv8pDXOIqQ
[envoyfilter_istio_-03-http-csrf filter-_csrf]: https://mp.weixin.qq.com/s/dlG9phV-kMMxs4UPzuRNYg
[envoyfilter_istio_http-jwt_authn-_RequestAuthorization]: https://mp.weixin.qq.com/s/IfrJ-FdLYsdhPkDrcO_YXA
[envoyfilter_istio_-05-fault-filter-_vs]: https://mp.weixin.qq.com/s/a4gDXqD8uswgglMwkUph2Q
[envoyfilter_istio_-06-http-match-_vs]: https://mp.weixin.qq.com/s/TpS3DHdcaJiPivIS_jsIGw
[envoyfilter_istio_-07-_dr]: https://mp.weixin.qq.com/s/k-zJm7n7OOKg6MotQJYPAA
[envoyfilter_istio_-08-]: https://mp.weixin.qq.com/s/n_bJ3saNeTtXRprIymhwzg
[envoyfilter_istio_-09-http-route filter]: https://mp.weixin.qq.com/s/JAeZr0BMVQxIrB3S_7Ru0A
[envoyfilter_istio_-network filter-redis proxy]: https://mp.weixin.qq.com/s/B9IPTI8F3q42nVkqbQRlPw
[envoyfilter_istio_-network filter-HttpConnectionManager]: https://mp.weixin.qq.com/s/W3OPQWkCVvuHGS49cTNhlg
[envoyfilter_istio_-ratelimit-istio ratelimit]: https://mp.weixin.qq.com/s/KgiDsELNol27mgZvDbFsqw
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2h4cGphdmEx_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20200524125723190.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2h4cGphdmEx,size_16,color_FFFFFF,t_70