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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防故障利器，你知道几个,istio新手不要读，太难！
不懂envoyfilter也敢说精通istio系列-http-rbac-不要只会用AuthorizationPolicy配置权限
不懂envoyfilter也敢说精通istio系列-02-http-corsFilter-不要只会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
不懂envoyfilter也敢说精通istio系列http-jwt_authn-不要只会RequestAuthorization
不懂envoyfilter也敢说精通istio系列-05-fault-filter-故障注入不止是vs
不懂envoyfilter也敢说精通istio系列-06-http-match-配置路由不只是vs
不懂envoyfilter也敢说精通istio系列-07-负载均衡配置不止是dr
不懂envoyfilter也敢说精通istio系列-08-连接池和断路器
不懂envoyfilter也敢说精通istio系列-09-http-route filter
不懂envoyfilter也敢说精通istio系列-network filter-redis proxy
不懂envoyfilter也敢说精通istio系列-network filter-HttpConnectionManager
不懂envoyfilter也敢说精通istio系列-ratelimit-istio ratelimit完全手册
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type DrainCmdOptions struct {//drain结构体
PrintFlags *genericclioptions.PrintFlags
ToPrinter func(string) (printers.ResourcePrinterFunc, error)
Namespace string
drainer *drain.Helper
nodeInfos []*resource.Info
genericclioptions.IOStreams
}func NewDrainCmdOptions(f cmdutil.Factory, ioStreams genericclioptions.IOStreams) *DrainCmdOptions {
o := &DrainCmdOptions{//初始化drain结构体
PrintFlags: genericclioptions.NewPrintFlags("drained").WithTypeSetter(scheme.Scheme),
IOStreams: ioStreams,
drainer: &drain.Helper{
GracePeriodSeconds: -1,
Out: ioStreams.Out,
ErrOut: ioStreams.ErrOut,
},
}
o.drainer.OnPodDeletedOrEvicted = o.onPodDeletedOrEvicted
return o
}//创建drain命令
func NewCmdDrain(f cmdutil.Factory, ioStreams genericclioptions.IOStreams) *cobra.Command {
o := NewDrainCmdOptions(f, ioStreams)//初始化结构体
cmd := &cobra.Command{//创建cobra命令
Use: "drain NODE",
DisableFlagsInUseLine: true,
Short: i18n.T("Drain node in preparation for maintenance"),
Long: drainLong,
Example: drainExample,
Run: func(cmd *cobra.Command, args []string) {
cmdutil.CheckErr(o.Complete(f, cmd, args))//准备
cmdutil.CheckErr(o.RunDrain())//运行
},
}
cmd.Flags().BoolVar(&o.drainer.Force, "force", o.drainer.Force, "Continue even if there are pods not managed by a ReplicationController, ReplicaSet, Job, DaemonSet or StatefulSet.")//force选项
cmd.Flags().BoolVar(&o.drainer.IgnoreAllDaemonSets, "ignore-daemonsets", o.drainer.IgnoreAllDaemonSets, "Ignore DaemonSet-managed pods.")//ignore-daemonsets选项
cmd.Flags().BoolVar(&o.drainer.DeleteLocalData, "delete-local-data", o.drainer.DeleteLocalData, "Continue even if there are pods using emptyDir (local data that will be deleted when the node is drained).")//delete-local-data选项
cmd.Flags().IntVar(&o.drainer.GracePeriodSeconds, "grace-period", o.drainer.GracePeriodSeconds, "Period of time in seconds given to each pod to terminate gracefully. If negative, the default value specified in the pod will be used.")//grace-period选项
cmd.Flags().DurationVar(&o.drainer.Timeout, "timeout", o.drainer.Timeout, "The length of time to wait before giving up, zero means infinite") //timeout选项
cmd.Flags().StringVarP(&o.drainer.Selector, "selector", "l", o.drainer.Selector, "Selector (label query) to filter on")//selector选项
cmd.Flags().StringVarP(&o.drainer.PodSelector, "pod-selector", "", o.drainer.PodSelector, "Label selector to filter pods on the node")//pod-selector选项
cmdutil.AddDryRunFlag(cmd)//干跑选项
return cmd
}//准备方法
func (o *DrainCmdOptions) Complete(f cmdutil.Factory, cmd *cobra.Command, args []string) error {
var err error
if len(args) == 0 && !cmd.Flags().Changed("selector") {//args和selector不能同时不指定
return cmdutil.UsageErrorf(cmd, fmt.Sprintf("USAGE: %s [flags]", cmd.Use))
}
if len(args) > 0 && len(o.drainer.Selector) > 0 {//args和selector不能同时指定
return cmdutil.UsageErrorf(cmd, "error: cannot specify both a node name and a --selector option")
}
o.drainer.DryRun = cmdutil.GetDryRunFlag(cmd)//设置干跑
if o.drainer.Client, err = f.KubernetesClientSet(); err != nil {//设置clientset
return err
}
if len(o.drainer.PodSelector) > 0 {//如果指定了pod-selector，解析
if _, err := labels.Parse(o.drainer.PodSelector); err != nil {
return errors.New("--pod-selector=<pod_selector> must be a valid label selector")
}
}
o.nodeInfos = []*resource.Info{}//构造Node info对象
o.Namespace, _, err = f.ToRawKubeConfigLoader().Namespace()//设置namespace
if err != nil {
return err
}
o.ToPrinter = func(operation string) (printers.ResourcePrinterFunc, error) {//printflag转printer函数
o.PrintFlags.NamePrintFlags.Operation = operation
if o.drainer.DryRun {
o.PrintFlags.Complete("%s (dry run)")
}
printer, err := o.PrintFlags.ToPrinter()
if err != nil {
return nil, err
}
return printer.PrintObj, nil
}
builder := f.NewBuilder().
WithScheme(scheme.Scheme, scheme.Scheme.PrioritizedVersionsAllGroups()...).
NamespaceParam(o.Namespace).DefaultNamespace().
ResourceNames("nodes", args...).
SingleResourceType().
Flatten()//用builder构造result对象
if len(o.drainer.Selector) > 0 {
builder = builder.LabelSelectorParam(o.drainer.Selector).
ResourceTypes("nodes")
}
r := builder.Do()//构造result对象
if err = r.Err(); err != nil {
return err
}
return r.Visit(func(info *resource.Info, err error) error {//visit result对象
if err != nil {
return err
}
if info.Mapping.Resource.GroupResource() != (schema.GroupResource{Group: "", Resource: "nodes"}) {//判断info为node
return fmt.Errorf("error: expected resource of type node, got %q", info.Mapping.Resource)
}
o.nodeInfos = append(o.nodeInfos, info)//append info
return nil
})
}//运行drain
func (o *DrainCmdOptions) RunDrain() error {
if err := o.RunCordonOrUncordon(true); err != nil {//先执行cordon
return err
}
printObj, err := o.ToPrinter("drained")//printflag转printer
if err != nil {
return err
}
drainedNodes := sets.NewString()//定义drainedNodes
var fatal error
for _, info := range o.nodeInfos {//遍历nodeinfo
var err error
if !o.drainer.DryRun {//如果非干跑
err = o.deleteOrEvictPodsSimple(info)//删除或驱逐pod
}
if err == nil || o.drainer.DryRun {//如果是干跑或者错误为空，drainedNode添加
drainedNodes.Insert(info.Name)
printObj(info.Object, o.Out)//打印结果
} else {// 如果非干跑
fmt.Fprintf(o.ErrOut, "error: unable to drain node %q, aborting command...\n\n", info.Name)//打印错误
remainingNodes := []string{}
fatal = err
for _, remainingInfo := range o.nodeInfos {//遍历Node info
if drainedNodes.Has(remainingInfo.Name) {//如果drainedNodes包含info则跳过
continue
}
remainingNodes = append(remainingNodes, remainingInfo.Name)//append没有drained的node
}
if len(remainingNodes) > 0 {//如果剩余的node大于0
fmt.Fprintf(o.ErrOut, "There are pending nodes to be drained:\n")
for _, nodeName := range remainingNodes {//打印提示
fmt.Fprintf(o.ErrOut, " %s\n", nodeName)
}
}
break
}
}
return fatal
}//删除或驱逐pod
func (o *DrainCmdOptions) deleteOrEvictPodsSimple(nodeInfo *resource.Info) error {
list, errs := o.drainer.GetPodsForDeletion(nodeInfo.Name)//获取node下的需要删除的pod
if errs != nil {
return utilerrors.NewAggregate(errs)
}
if warnings := list.Warnings(); warnings != "" {//打印告警
fmt.Fprintf(o.ErrOut, "WARNING: %s\n", warnings)
}
if err := o.drainer.DeleteOrEvictPods(list.Pods()); err != nil {//执行删除或驱逐pod
pendingList, newErrs := o.drainer.GetPodsForDeletion(nodeInfo.Name)//获取没有被删除或驱逐的pod
fmt.Fprintf(o.ErrOut, "There are pending pods in node %q when an error occurred: %v\n", nodeInfo.Name, err)//打印告警
for _, pendingPod := range pendingList.Pods() {//打印pod pending
fmt.Fprintf(o.ErrOut, "%s/%s\n", "pod", pendingPod.Name)
}
if newErrs != nil {
fmt.Fprintf(o.ErrOut, "following errors also occurred:\n%s", utilerrors.NewAggregate(newErrs))
}
return err
}
return nil
}//执行删除或驱逐pod
func (d *Helper) DeleteOrEvictPods(pods []corev1.Pod) error {
if len(pods) == 0 {//pod为空返回
return nil
}
policyGroupVersion, err := CheckEvictionSupport(d.Client)//判断是否支持evict
if err != nil {
return err
}
// TODO(justinsb): unnecessary?
getPodFn := func(namespace, name string) (*corev1.Pod, error) {//获取pod的函数
return d.Client.CoreV1().Pods(namespace).Get(name, metav1.GetOptions{})
}
if len(policyGroupVersion) > 0 {//如果支持驱逐
return d.evictPods(pods, policyGroupVersion, getPodFn)//驱逐pod
}
return d.deletePods(pods, getPodFn)//删除pod
}//驱逐pod
func (d *Helper) evictPods(pods []corev1.Pod, policyGroupVersion string, getPodFn func(namespace, name string) (*corev1.Pod, error)) error {
returnCh := make(chan error, 1)//创建return channel
for _, pod := range pods {//遍历pod
go func(pod corev1.Pod, returnCh chan error) {//运行go routine
for {
fmt.Fprintf(d.Out, "evicting pod %q\n", pod.Name)//打印驱逐pod
err := d.EvictPod(pod, policyGroupVersion)//执行驱逐pod
if err == nil {//如果error为nil，跳出循环
break
} else if apierrors.IsNotFound(err) {
returnCh <- nil//如果报没找到错误，往channel里放nil
return
} else if apierrors.IsTooManyRequests(err) {//如果错误是太多请求
fmt.Fprintf(d.ErrOut, "error when evicting pod %q (will retry after 5s): %v\n", pod.Name, err)
time.Sleep(5 * time.Second)//休息5秒
} else {
returnCh <- fmt.Errorf("error when evicting pod %q: %v", pod.Name, err)//往channel放一个错误
return
}
}
_, err := waitForDelete([]corev1.Pod{pod}, 1*time.Second, time.Duration(math.MaxInt64), true, getPodFn, d.OnPodDeletedOrEvicted)//等待pod删除完成
if err == nil {//error为空，往channel放nil
returnCh <- nil
} else {//否则往channel放错误
returnCh <- fmt.Errorf("error when waiting for pod %q terminating: %v", pod.Name, err)
}
}(pod, returnCh)//调用go routine
}
doneCount := 0//完成数量
var errors []error
// 0 timeout means infinite, we use MaxInt64 to represent it.
var globalTimeout time.Duration//全局超时时间
if d.Timeout == 0 {//如果没有指定超时，则为最大整数
globalTimeout = time.Duration(math.MaxInt64)
} else {//如果指定了超时，则指定超时时间
globalTimeout = d.Timeout
}
globalTimeoutCh := time.After(globalTimeout)//超时channel
numPods := len(pods)//需要evit的pod数量
for doneCount < numPods {//如果完成数量不等于需要完成的数量，则一直循环
select {
case err := <-returnCh://从channel里获取值
doneCount++//完成数量加1
if err != nil {//如果有错误append错误
errors = append(errors, err)
}
case <-globalTimeoutCh://如果超时，返回错误
return fmt.Errorf("drain did not complete within %v", globalTimeout)
}
}
return utilerrors.NewAggregate(errors)
}//执行删除pod
func (d *Helper) deletePods(pods []corev1.Pod, getPodFn func(namespace, name string) (*corev1.Pod, error)) error {
// 0 timeout means infinite, we use MaxInt64 to represent it.
var globalTimeout time.Duration//设置超时时间
if d.Timeout == 0 {
globalTimeout = time.Duration(math.MaxInt64)
} else {
globalTimeout = d.Timeout
}
for _, pod := range pods {//遍历pod执行删除
err := d.DeletePod(pod)
if err != nil && !apierrors.IsNotFound(err) {
return err
}
}
_, err := waitForDelete(pods, 1*time.Second, globalTimeout, false, getPodFn, d.OnPodDeletedOrEvicted)//等待删除完成
return err
}
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