kubectl源码分析之rollout undo

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原创最新推荐文章于 2026-07-15 12:13:09 发布 600 阅读 AI 写同款· GEO 优化 ›

kubectl滚动更新资源 rollout Manage the rollout of a resource. Valid resource types include: * deployments * daemonsets * statefulsets Examples: # Rollback to the previous deployment kubectl rollout undo deployment/abc # Check the rollout status of a da 阅读详情

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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多集群链路追踪，附实操视频

istio防故障利器，你知道几个,istio新手不要读，太难！

istio业务权限控制，原来可以这么玩

istio实现非侵入压缩，微服务之间如何实现压缩

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

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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

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

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type UndoOptions struct {//undo结构体
	PrintFlags *genericclioptions.PrintFlags
	ToPrinter  func(string) (printers.ResourcePrinter, error)

	Builder          func() *resource.Builder
	ToRevision       int64
	DryRun           bool
	Resources        []string
	Namespace        string
	EnforceNamespace bool
	RESTClientGetter genericclioptions.RESTClientGetter

	resource.FilenameOptions
	genericclioptions.IOStreams
}

func NewRolloutUndoOptions(streams genericclioptions.IOStreams) *UndoOptions {
	return &UndoOptions{//初始化结构体
		PrintFlags: genericclioptions.NewPrintFlags("rolled back").WithTypeSetter(scheme.Scheme),
		IOStreams:  streams,
		ToRevision: int64(0),
	}
}

//创建undo命令
func NewCmdRolloutUndo(f cmdutil.Factory, streams genericclioptions.IOStreams) *cobra.Command {
	o := NewRolloutUndoOptions(streams)//初始化结构体

	validArgs := []string{"deployment", "daemonset", "statefulset"}

	cmd := &cobra.Command{//创建cobra命令
		Use:                   "undo (TYPE NAME | TYPE/NAME) [flags]",
		DisableFlagsInUseLine: true,
		Short:                 i18n.T("Undo a previous rollout"),
		Long:                  undoLong,
		Example:               undoExample,
		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.RunUndo())//运行
		},
		ValidArgs: validArgs,//有效参数
	}

	cmd.Flags().Int64Var(&o.ToRevision, "to-revision", o.ToRevision, "The revision to rollback to. Default to 0 (last revision).")//to-revision选项
	usage := "identifying the resource to get from a server."
	cmdutil.AddFilenameOptionFlags(cmd, &o.FilenameOptions, usage)//文件选项
	cmdutil.AddDryRunFlag(cmd)//干跑选项
	o.PrintFlags.AddFlags(cmd)//打印选项
	return cmd
}

//准备函数
func (o *UndoOptions) Complete(f cmdutil.Factory, cmd *cobra.Command, args []string) error {
	o.Resources = args//设置资源
	o.DryRun = cmdutil.GetDryRunFlag(cmd)//设置干跑

	var err error
	if o.Namespace, o.EnforceNamespace, err = f.ToRawKubeConfigLoader().Namespace(); err != nil {//设置Namespace和EnforceNamespace
		return err
	}

	o.ToPrinter = func(operation string) (printers.ResourcePrinter, error) {//printflag转printer函数
		o.PrintFlags.NamePrintFlags.Operation = operation
		if o.DryRun {
			o.PrintFlags.Complete("%s (dry run)")
		}
		return o.PrintFlags.ToPrinter()
	}

	o.RESTClientGetter = f//设置RestClientGetter
	o.Builder = f.NewBuilder//设置Builder

	return err
}

//校验函数
func (o *UndoOptions) Validate() error {
	if len(o.Resources) == 0 && cmdutil.IsFilenameSliceEmpty(o.Filenames, o.Kustomize) {//资源和文件至少有一个
		return fmt.Errorf("required resource not specified")
	}
	return nil
}

//运行
func (o *UndoOptions) RunUndo() error {
	r := o.Builder().
		WithScheme(scheme.Scheme, scheme.Scheme.PrioritizedVersionsAllGroups()...).
		NamespaceParam(o.Namespace).DefaultNamespace().
		FilenameParam(o.EnforceNamespace, &o.FilenameOptions).
		ResourceTypeOrNameArgs(true, o.Resources...).
		ContinueOnError().
		Latest().
		Flatten().
		Do()//构造REsult对象
	if err := r.Err(); err != nil {
		return err
	}

	err := r.Visit(func(info *resource.Info, err error) error {//visit Result
		if err != nil {
			return err
		}
		rollbacker, err := polymorphichelpers.RollbackerFn(o.RESTClientGetter, info.ResourceMapping())//获取回滚器
		if err != nil {
			return err
		}

		result, err := rollbacker.Rollback(info.Object, nil, o.ToRevision, o.DryRun)//执行回滚
		if err != nil {
			return err
		}

		printer, err := o.ToPrinter(result)//print flag转printer
		if err != nil {
			return err
		}

		return printer.PrintObj(info.Object, o.Out)//打印结果
	})

	return err
}

//执行回滚
func (r *DeploymentRollbacker) Rollback(obj runtime.Object, updatedAnnotations map[string]string, toRevision int64, dryRun bool) (string, error) {
	if toRevision < 0 {//回滚范本不能小于0
		return "", revisionNotFoundErr(toRevision)
	}
	accessor, err := meta.Accessor(obj)//访问对象
	if err != nil {
		return "", fmt.Errorf("failed to create accessor for kind %v: %s", obj.GetObjectKind(), err.Error())
	}
	name := accessor.GetName()//获取obj名称
	namespace := accessor.GetNamespace()//获取obj namespace

	// TODO: Fix this after kubectl has been removed from core. It is not possible to convert the runtime.Object
	// to the external appsv1 Deployment without round-tripping through an internal version of Deployment. We're
	// currently getting rid of all internal versions of resources. So we specifically request the appsv1 version
	// here. This follows the same pattern as for DaemonSet and StatefulSet.
	deployment, err := r.c.AppsV1().Deployments(namespace).Get(name, metav1.GetOptions{})//获取deployment
	if err != nil {
		return "", fmt.Errorf("failed to retrieve Deployment %s: %v", name, err)
	}

	rsForRevision, err := deploymentRevision(deployment, r.c, toRevision)//获取对应版本的rs
	if err != nil {
		return "", err
	}
	if dryRun {//如果是干盘返回
		return printTemplate(&rsForRevision.Spec.Template)
	}
	if deployment.Spec.Paused {//如果deploy已经暂停，返回错误
		return "", fmt.Errorf("you cannot rollback a paused deployment; resume it first with 'kubectl rollout resume deployment/%s' and try again", name)
	}

	// Skip if the revision already matches current Deployment
	if equalIgnoreHash(&rsForRevision.Spec.Template, &deployment.Spec.Template) {//如果要更新的rs的template和现在的deploy的template一样则，返回提示template一样
		return fmt.Sprintf("%s (current template already matches revision %d)", rollbackSkipped, toRevision), nil
	}

	// remove hash label before patching back into the deployment
	delete(rsForRevision.Spec.Template.Labels, appsv1.DefaultDeploymentUniqueLabelKey)//删除rs的pod-template-hash标签

	// compute deployment annotations
	annotations := map[string]string{}//设置annotation
	for k := range annotationsToSkip {
		if v, ok := deployment.Annotations[k]; ok {
			annotations[k] = v
		}
	}
	for k, v := range rsForRevision.Annotations {
		if !annotationsToSkip[k] {
			annotations[k] = v
		}
	}

	// make patch to restore
	patchType, patch, err := getDeploymentPatch(&rsForRevision.Spec.Template, annotations)//获取patch
	if err != nil {
		return "", fmt.Errorf("failed restoring revision %d: %v", toRevision, err)
	}

	// Restore revision
	if _, err = r.c.AppsV1().Deployments(namespace).Patch(name, patchType, patch); err != nil {//应用patch到服务端
		return "", fmt.Errorf("failed restoring revision %d: %v", toRevision, err)
	}
	return rollbackSuccess, nil//返回成功
}