operator开发脚手架

1、脚手架工具

Operator的实现方式主要包括OperatorSDK和KubeBuilder，目前KubeBuilder在阿里使用的比较多。

KubeBuilder

OperatorSDK

我们这里主要是用KubeBuilder来进行，其中OperatorSDK其实也是应用了KubeBuilder。

2、创建Operator工程

创建脚手架工程：

mkdir myapp-operator
cd myapp-operator/
go env -w GO111MODULE=on
go env -w GOPROXY=https://goproxy.cn,direct
kubebuilder init --domain kubenode.kingtest.com

创建脚手架结果：

kubebuilder init --domain kubenode.kingtest.com
INFO Writing kustomize manifests for you to edit... 
INFO Writing scaffold for you to edit...          
INFO Get controller runtime:
$ go get sigs.k8s.io/controller-runtime@v0.19.0 
go: downloading sigs.k8s.io/controller-runtime v0.19.0
go: downloading k8s.io/apimachinery v0.31.0
go: downloading k8s.io/api v0.31.0
go: downloading k8s.io/client-go v0.31.0
go: downloading k8s.io/utils v0.0.0-20240711033017-18e509b52bc8
go: downloading github.com/go-logr/logr v1.4.2
go: downloading k8s.io/klog/v2 v2.130.1
go: downloading golang.org/x/exp v0.0.0-20230515195305-f3d0a9c9a5cc
go: downloading github.com/evanphx/json-patch/v5 v5.9.0
go: downloading github.com/prometheus/client_golang v1.19.1
go: downloading gomodules.xyz/jsonpatch/v2 v2.4.0
go: downloading github.com/gogo/protobuf v1.3.2
go: downloading github.com/google/gofuzz v1.2.0
go: downloading sigs.k8s.io/structured-merge-diff/v4 v4.4.1
go: downloading k8s.io/apiextensions-apiserver v0.31.0
go: downloading sigs.k8s.io/json v0.0.0-20221116044647-bc3834ca7abd
go: downloading k8s.io/kube-openapi v0.0.0-20240228011516-70dd3763d340
go: downloading github.com/google/uuid v1.6.0
go: downloading github.com/prometheus/client_model v0.6.1
go: downloading github.com/prometheus/common v0.55.0
go: downloading github.com/fsnotify/fsnotify v1.7.0
go: downloading golang.org/x/net v0.26.0
go: downloading gopkg.in/inf.v0 v0.9.1
go: downloading github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da
go: downloading github.com/imdario/mergo v0.3.6
go: downloading github.com/spf13/pflag v1.0.5
go: downloading golang.org/x/term v0.21.0
go: downloading github.com/golang/protobuf v1.5.4
go: downloading github.com/google/gnostic-models v0.6.8
go: downloading golang.org/x/time v0.3.0
go: downloading sigs.k8s.io/yaml v1.4.0
go: downloading github.com/beorn7/perks v1.0.1
go: downloading github.com/cespare/xxhash/v2 v2.3.0
go: downloading github.com/prometheus/procfs v0.15.1
go: downloading golang.org/x/sys v0.21.0
go: downloading google.golang.org/protobuf v1.34.2
go: downloading golang.org/x/oauth2 v0.21.0
go: downloading github.com/json-iterator/go v1.1.12
go: downloading gopkg.in/yaml.v2 v2.4.0
go: downloading github.com/fxamacker/cbor/v2 v2.7.0
go: downloading github.com/google/go-cmp v0.6.0
go: downloading gopkg.in/yaml.v3 v3.0.1
go: downloading github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc
go: downloading github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822
go: downloading github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd
go: downloading github.com/modern-go/reflect2 v1.0.2
go: downloading github.com/go-openapi/jsonreference v0.20.2
go: downloading github.com/go-openapi/swag v0.22.4
go: downloading golang.org/x/text v0.16.0
go: downloading github.com/go-openapi/jsonpointer v0.19.6
go: downloading github.com/emicklei/go-restful/v3 v3.11.0
go: downloading github.com/mailru/easyjson v0.7.7
go: downloading github.com/josharian/intern v1.0.0
go: downloading github.com/x448/float16 v0.8.4
go: downloading github.com/pkg/errors v0.9.1
INFO Update dependencies:
$ go mod tidy           
go: downloading github.com/onsi/ginkgo/v2 v2.19.0
go: downloading github.com/stretchr/testify v1.9.0
go: downloading github.com/onsi/gomega v1.33.1
go: downloading github.com/go-logr/zapr v1.3.0
go: downloading go.uber.org/zap v1.26.0
go: downloading k8s.io/apiserver v0.31.0
go: downloading go.uber.org/goleak v1.3.0
go: downloading github.com/evanphx/json-patch v0.5.2
go: downloading gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c
go: downloading gopkg.in/evanphx/json-patch.v4 v4.12.0
go: downloading github.com/kr/pretty v0.3.1
go: downloading go.uber.org/multierr v1.11.0
go: downloading github.com/go-task/slim-sprig/v3 v3.0.0
go: downloading golang.org/x/tools v0.21.1-0.20240508182429-e35e4ccd0d2d
go: downloading github.com/google/pprof v0.0.0-20240525223248-4bfdf5a9a2af
go: downloading github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2
go: downloading github.com/rogpeppe/go-internal v1.12.0
go: downloading github.com/kr/text v0.2.0
go: downloading k8s.io/component-base v0.31.0
go: downloading go.opentelemetry.io/otel v1.28.0
go: downloading go.opentelemetry.io/otel/trace v1.28.0
go: downloading google.golang.org/grpc v1.65.0
go: downloading sigs.k8s.io/apiserver-network-proxy/konnectivity-client v0.30.3
go: downloading golang.org/x/sync v0.7.0
go: downloading github.com/google/cel-go v0.20.1
go: downloading github.com/blang/semver/v4 v4.0.0
go: downloading go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.53.0
go: downloading go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc v1.27.0
go: downloading go.opentelemetry.io/otel/sdk v1.28.0
go: downloading google.golang.org/genproto/googleapis/api v0.0.0-20240528184218-531527333157
go: downloading github.com/felixge/httpsnoop v1.0.4
go: downloading go.opentelemetry.io/otel/metric v1.28.0
go: downloading github.com/asaskevich/govalidator v0.0.0-20190424111038-f61b66f89f4a
go: downloading github.com/go-logr/stdr v1.2.2
go: downloading google.golang.org/genproto/googleapis/rpc v0.0.0-20240701130421-f6361c86f094
go: downloading github.com/antlr4-go/antlr/v4 v4.13.0
go: downloading google.golang.org/genproto v0.0.0-20230822172742-b8732ec3820d
go: downloading github.com/spf13/cobra v1.8.1
go: downloading github.com/stoewer/go-strcase v1.2.0
go: downloading github.com/inconshreveable/mousetrap v1.1.0
go: downloading go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.28.0
go: downloading github.com/cenkalti/backoff/v4 v4.3.0
go: downloading go.opentelemetry.io/proto/otlp v1.3.1
go: downloading github.com/grpc-ecosystem/grpc-gateway/v2 v2.20.0
go: downloading github.com/grpc-ecosystem/grpc-gateway v1.16.0
Next: define a resource with:
$ kubebuilder create api

本步骤创建了 Go module 工程的模板文件，引入了必要的依赖。
这里先设置了go的代理，不然会无法下载依赖。
第一次新建工程时，会下载一些依赖(go: downloading 。。。)
查看此时的项目结构:

.
├── cmd
│   └── main.go
├── config
│   ├── default
│   │   ├── kustomization.yaml
│   │   ├── manager_metrics_patch.yaml
│   │   └── metrics_service.yaml
│   ├── manager
│   │   ├── kustomization.yaml
│   │   └── manager.yaml
│   ├── network-policy
│   │   ├── allow-metrics-traffic.yaml
│   │   └── kustomization.yaml
│   ├── prometheus
│   │   ├── kustomization.yaml
│   │   └── monitor.yaml
│   └── rbac
│       ├── kustomization.yaml
│       ├── leader_election_role_binding.yaml
│       ├── leader_election_role.yaml
│       ├── metrics_auth_role_binding.yaml
│       ├── metrics_auth_role.yaml
│       ├── metrics_reader_role.yaml
│       ├── role_binding.yaml
│       ├── role.yaml
│       └── service_account.yaml
├── Dockerfile
├── go.mod
├── go.sum
├── hack
│   └── boilerplate.go.txt
├── Makefile
├── PROJECT
├── README.md
└── test
    ├── e2e
    │   ├── e2e_suite_test.go
    │   └── e2e_test.go
    └── utils
        └── utils.go

12 directories, 29 files

创建API，生成CRD和Controller:

kubebuilder create api --group apps --version v1 --kind Myapp

参数含义：

• group参数表示组的概念
• version定义版本
• kind定义自定义资源类型
• 以上参数组成 自定义yaml 的 apiVersion和kind
• 执行kubebuilder create api时直接带上–namespaced=false可以将该对象设计为集群级别（类似node、pv）

创建API结果：

kubebuilder create api --group apps --version v1 --kind Myapp
INFO Create Resource [y/n]                        
y
INFO Create Controller [y/n]                      
y
INFO Writing kustomize manifests for you to edit... 
INFO Writing scaffold for you to edit...          
INFO api/v1/myapp_types.go                        
INFO api/v1/groupversion_info.go                  
INFO internal/controller/suite_test.go            
INFO internal/controller/myapp_controller.go      
INFO internal/controller/myapp_controller_test.go 
INFO Update dependencies:
$ go mod tidy           
INFO Running make:
$ make generate                
mkdir -p /home/king/workspace/king-devops/operator/myapp-operator/bin
Downloading sigs.k8s.io/controller-tools/cmd/controller-gen@v0.16.1
go: downloading sigs.k8s.io/controller-tools v0.16.1
go: downloading github.com/fatih/color v1.17.0
go: downloading golang.org/x/tools v0.24.0
go: downloading github.com/gobuffalo/flect v1.0.2
go: downloading golang.org/x/net v0.28.0
go: downloading github.com/mattn/go-isatty v0.0.20
go: downloading github.com/mattn/go-colorable v0.1.13
go: downloading golang.org/x/sys v0.23.0
go: downloading golang.org/x/sync v0.8.0
go: downloading golang.org/x/mod v0.20.0
go: downloading golang.org/x/text v0.17.0
/home/king/workspace/king-devops/operator/myapp-operator/bin/controller-gen object:headerFile="hack/boilerplate.go.txt" paths="./..."
Next: implement your new API and generate the manifests (e.g. CRDs,CRs) with:
$ make manifests

此时的目录结构：

.
├── api
│   └── v1
│       ├── groupversion_info.go
│       ├── myapp_types.go
│       └── zz_generated.deepcopy.go
├── bin
│   ├── controller-gen -> /home/king/workspace/king-devops/operator/myapp-operator/bin/controller-gen-v0.16.1
│   └── controller-gen-v0.16.1
├── cmd
│   └── main.go
├── config
│   ├── crd
│   │   ├── kustomization.yaml
│   │   └── kustomizeconfig.yaml
│   ├── default
│   │   ├── kustomization.yaml
│   │   ├── manager_metrics_patch.yaml
│   │   └── metrics_service.yaml
│   ├── manager
│   │   ├── kustomization.yaml
│   │   └── manager.yaml
│   ├── network-policy
│   │   ├── allow-metrics-traffic.yaml
│   │   └── kustomization.yaml
│   ├── prometheus
│   │   ├── kustomization.yaml
│   │   └── monitor.yaml
│   ├── rbac
│   │   ├── kustomization.yaml
│   │   ├── leader_election_role_binding.yaml
│   │   ├── leader_election_role.yaml
│   │   ├── metrics_auth_role_binding.yaml
│   │   ├── metrics_auth_role.yaml
│   │   ├── metrics_reader_role.yaml
│   │   ├── myapp_editor_role.yaml
│   │   ├── myapp_viewer_role.yaml
│   │   ├── role_binding.yaml
│   │   ├── role.yaml
│   │   └── service_account.yaml
│   └── samples
│       ├── apps_v1_myapp.yaml
│       └── kustomization.yaml
├── Dockerfile
├── go.mod
├── go.sum
├── hack
│   └── boilerplate.go.txt
├── internal
│   └── controller
│       ├── myapp_controller.go
│       ├── myapp_controller_test.go
│       └── suite_test.go
├── Makefile
├── PROJECT
├── README.md
└── test
    ├── e2e
    │   ├── e2e_suite_test.go
    │   └── e2e_test.go
    └── utils
        └── utils.go

19 directories, 43 files

如果需要在Nginx CRUD 时进行合法性检查， 可以生成webhook:

kubebuilder create webhook --group apps --version v1 --kind Myapp --conversion --defaulting --programmatic-validation

参数含义：

• group参数表示组的概念
• version定义版本
• kind定义自定义资源类型
• 以上参数组成 自定义yaml 的 apiVersion和kind
• defaulting：默认值设置（Defaulting） 的目的是在CRD对象创建或更新时，如果某些字段没有被显式设置值，自动为其填充一个合理的默认值。这对于确保资源实例有一套统一的、预先定义的配置非常有用，可以减少用户的配置负担，并保证资源的一致性。例如，如果你定义了一个监控应用的CRD，可能希望默认开启日志记录功能，除非用户明确关闭它。
• programmatic-validation：程序化验证（Programmatic Validation） 则是在CRD对象创建或更新前，对提交的数据进行逻辑验证的机制。与CRD schema提供的静态验证相比，程序化验证可以实现更加复杂的业务逻辑验证。这意味着你可以在webhook服务中编写代码来检查CRD实例的数据是否满足特定的业务规则或约束条件。例如，你可以验证一个资源请求的内存配额是否超过了集群的最大允许值，或者确保引用的其他资源确实存在。
• conversion：自动数据迁移：conversion webhook可以在后台自动将CRD的一个版本转换为另一个版本，无需人工干预，从而简化了版本升级过程。
  • 兼容性保障：即使API发生变化，也能确保旧客户端和新客户端都能够正常工作，提高了系统的向后和向前兼容性。
  • 复杂逻辑处理：对于简单的字段添加或删除，Kubernetes的自动转换器可能足够用。但涉及到复杂的数据结构调整或逻辑变换时，就需要自定义conversion webhook来精确控制转换过程。

执行结果：

kubebuilder create webhook --group apps --version v1 --kind Myapp --conversion --defaulting --programmatic-validation
INFO Writing kustomize manifests for you to edit... 
INFO Writing scaffold for you to edit...          
INFO api/v1/myapp_webhook.go                      
INFO api/v1/myapp_webhook_test.go                 
INFO Webhook server has been set up for you.
You need to implement the conversion.Hub and conversion.Convertible interfaces for your CRD types. 
INFO api/v1/webhook_suite_test.go                 
INFO Update dependencies:
$ go mod tidy           
INFO Running make:
$ make generate                
/home/king/workspace/king-devops/operator/myapp-operator/bin/controller-gen object:headerFile="hack/boilerplate.go.txt" paths="./..."
Next: implement your new Webhook and generate the manifests with:
$ make manifests

此时目录结构：

.
├── api
│   └── v1
│       ├── groupversion_info.go
│       ├── myapp_types.go
│       ├── myapp_webhook.go
│       ├── myapp_webhook_test.go
│       ├── webhook_suite_test.go
│       └── zz_generated.deepcopy.go
├── bin
│   ├── controller-gen -> /home/king/workspace/king-devops/operator/myapp-operator/bin/controller-gen-v0.16.1
│   └── controller-gen-v0.16.1
├── cmd
│   └── main.go
├── config
│   ├── certmanager
│   │   ├── certificate.yaml
│   │   ├── kustomization.yaml
│   │   └── kustomizeconfig.yaml
│   ├── crd
│   │   ├── kustomization.yaml
│   │   ├── kustomizeconfig.yaml
│   │   └── patches
│   │       ├── cainjection_in_myapps.yaml
│   │       └── webhook_in_myapps.yaml
│   ├── default
│   │   ├── kustomization.yaml
│   │   ├── manager_metrics_patch.yaml
│   │   ├── manager_webhook_patch.yaml
│   │   ├── metrics_service.yaml
│   │   └── webhookcainjection_patch.yaml
│   ├── manager
│   │   ├── kustomization.yaml
│   │   └── manager.yaml
│   ├── network-policy
│   │   ├── allow-metrics-traffic.yaml
│   │   ├── allow-webhook-traffic.yaml
│   │   └── kustomization.yaml
│   ├── prometheus
│   │   ├── kustomization.yaml
│   │   └── monitor.yaml
│   ├── rbac
│   │   ├── kustomization.yaml
│   │   ├── leader_election_role_binding.yaml
│   │   ├── leader_election_role.yaml
│   │   ├── metrics_auth_role_binding.yaml
│   │   ├── metrics_auth_role.yaml
│   │   ├── metrics_reader_role.yaml
│   │   ├── myapp_editor_role.yaml
│   │   ├── myapp_viewer_role.yaml
│   │   ├── role_binding.yaml
│   │   ├── role.yaml
│   │   └── service_account.yaml
│   ├── samples
│   │   ├── apps_v1_myapp.yaml
│   │   └── kustomization.yaml
│   └── webhook
│       ├── kustomization.yaml
│       ├── kustomizeconfig.yaml
│       └── service.yaml
├── Dockerfile
├── go.mod
├── go.sum
├── hack
│   └── boilerplate.go.txt
├── internal
│   └── controller
│       ├── myapp_controller.go
│       ├── myapp_controller_test.go
│       └── suite_test.go
├── Makefile
├── PROJECT
├── README.md
└── test
    ├── e2e
    │   ├── e2e_suite_test.go
    │   └── e2e_test.go
    └── utils
        └── utils.go

22 directories, 57 files

最终的工程结构：

.
├── api
│   └── v1
│       ├── groupversion_info.go
│       ├── myapp_types.go
│       ├── myapp_webhook.go
│       ├── myapp_webhook_test.go
│       ├── webhook_suite_test.go
│       └── zz_generated.deepcopy.go
├── bin
│   ├── controller-gen -> /home/king/workspace/king-devops/operator/myapp-operator/bin/controller-gen-v0.16.1
│   └── controller-gen-v0.16.1
├── cmd
│   └── main.go
├── config
│   ├── certmanager
│   │   ├── certificate.yaml
│   │   ├── kustomization.yaml
│   │   └── kustomizeconfig.yaml
│   ├── crd
│   │   ├── kustomization.yaml
│   │   ├── kustomizeconfig.yaml
│   │   └── patches
│   │       ├── cainjection_in_myapps.yaml
│   │       └── webhook_in_myapps.yaml
│   ├── default
│   │   ├── kustomization.yaml
│   │   ├── manager_metrics_patch.yaml
│   │   ├── manager_webhook_patch.yaml
│   │   ├── metrics_service.yaml
│   │   └── webhookcainjection_patch.yaml
│   ├── manager
│   │   ├── kustomization.yaml
│   │   └── manager.yaml
│   ├── network-policy
│   │   ├── allow-metrics-traffic.yaml
│   │   ├── allow-webhook-traffic.yaml
│   │   └── kustomization.yaml
│   ├── prometheus
│   │   ├── kustomization.yaml
│   │   └── monitor.yaml
│   ├── rbac
│   │   ├── kustomization.yaml
│   │   ├── leader_election_role_binding.yaml
│   │   ├── leader_election_role.yaml
│   │   ├── metrics_auth_role_binding.yaml
│   │   ├── metrics_auth_role.yaml
│   │   ├── metrics_reader_role.yaml
│   │   ├── myapp_editor_role.yaml
│   │   ├── myapp_viewer_role.yaml
│   │   ├── role_binding.yaml
│   │   ├── role.yaml
│   │   └── service_account.yaml
│   ├── samples
│   │   ├── apps_v1_myapp.yaml
│   │   └── kustomization.yaml
│   └── webhook
│       ├── kustomization.yaml
│       ├── kustomizeconfig.yaml
│       └── service.yaml
├── Dockerfile
├── go.mod
├── go.sum
├── hack
│   └── boilerplate.go.txt
├── internal
│   └── controller
│       ├── myapp_controller.go
│       ├── myapp_controller_test.go
│       └── suite_test.go
├── Makefile
├── PROJECT
├── README.md
└── test
    ├── e2e
    │   ├── e2e_suite_test.go
    │   └── e2e_test.go
    └── utils
        └── utils.go

22 directories, 57 files

关键目录及其内容的概述：

• Dockerfile: 定义了用于构建Operator容器镜像的Docker配置文件。
• Makefile: 包含了一系列预定义的Make任务，用于构建、测试、运行和部署Operator。
• PROJECT: 存储项目元数据的文件，Kubebuilder使用它来跟踪项目的状态和配置。
• README.md: 项目的主要说明文档，通常包含项目简介、安装指南、开发流程等信息。
• api/v1: 定义了自定义资源定义(CRD)的目录，其中包含了资源的Go类型定义及DeepCopy生成文件。
  • myapp_types.go: 资源类型的定义(myapp_types.go)
  • myapp_webhook.go: webhook逻辑
  • zz_generated.deepcopy.go: 深拷贝生成代码
  • groupversion_info.go: 定义了API组和版本信息。
• bin: 存放项目依赖的可执行文件，如controller-gen，用于CRD代码生成。
• cmd/main.go: Operator的入口点，负责初始化和运行控制器。
• config: 配置目录，包含用于Kubernetes资源部署的各种Kustomize配置。
  • crd/: 用于CRD资源的Kustomize配置。
  • default/: 应用默认的RBAC、服务等配置。
  • manager/: Operator Manager的部署配置。
  • network-policy/, prometheus/, rbac/, samples/: 分别包含网络策略、Prometheus监控配置、RBAC规则和示例资源的配置。
• go.mod, go.sum: Go模块管理文件，记录项目依赖。
• hack/boilerplate.go.txt: 用于代码生成的模板文件，保持版权头部一致性。
• internal/controller: Operator控制器的核心逻辑所在，包含监控资源(Myapp)的控制器实现。
• test: 测试相关目录。
  • e2e/: 端到端测试代码，验证整个Operator在Kubernetes集群上的行为。
  • utils/: 测试辅助工具和函数。

3、编写代码

下面主要以Deployment为例，核心逻辑是把自定义CR（Myapp）当做终态，把Deployment当做运行态，通过比对属性的不一致，编写相关的Reconcile逻辑。

一张图解释各种资源和 Controller 的关系：

3.1 定义 CRD

在api/v1/myapp_type.go中定义 Spec 和 Status

// MyappSpec defines the desired state of Myapp
type MyappSpec struct {
        // INSERT ADDITIONAL SPEC FIELDS - desired state of cluster
        // Important: Run "make" to regenerate code after modifying this file

        // Foo is an example field of Myapp. Edit myapp_types.go to remove/update
        Foo                   string `json:"foo,omitempty"`
        appsv1.DeploymentSpec `json:",inline"`
}

// MyappStatus defines the observed state of Myapp
type MyappStatus struct {
        // INSERT ADDITIONAL STATUS FIELD - define observed state of cluster
        // Important: Run "make" to regenerate code after modifying this file
        appsv1.DeploymentSpec `json:",inline"`
}

// +kubebuilder:object:root=true
// +kubebuilder:subresource:status

// Myapp is the Schema for the myapps API
type Myapp struct {
        metav1.TypeMeta   `json:",inline"`
        metav1.ObjectMeta `json:"metadata,omitempty"`

        Spec   MyappSpec   `json:"spec,omitempty"`
        Status MyappStatus `json:"status,omitempty"`
}

注意+kubebuilder并非普通注释，不能随意删除。

3.2 编写Reconcile逻辑

在internal/controller/myapp_controller.go中实现 Reconcile 逻辑

func (r *MyappReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
        logger := log.FromContext(ctx)

        // TODO(user): your logic here
        logger.Info("start Reconcile" + req.Name)

        return ctrl.Result{}, nil
}

3.3 修改Webhook

在api/v1/myapp_webhook.go中根据需要进行修改

func (r *Myapp) ValidateCreate() error 
func (r *Myapp) ValidateUpdate(old runtime.Object) error
func (r *Myapp) Default()

3.4 修改main入口

以前的老版本kubebuilder生成的项目，需要在cmd/main.go添加监听的namespace
但是新版本没有这个信息，以下是示例：

mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrl.Options{
                Scheme:                 scheme,
                Metrics:                metricsServerOptions,
                WebhookServer:          webhookServer,
                HealthProbeBindAddress: probeAddr,
                LeaderElection:         enableLeaderElection,
                LeaderElectionID:       "6a511ed4.kubenode.kingtest.com",
                // LeaderElectionReleaseOnCancel defines if the leader should step down voluntarily
                // when the Manager ends. This requires the binary to immediately end when the
                // Manager is stopped, otherwise, this setting is unsafe. Setting this significantly
                // speeds up voluntary leader transitions as the new leader don't have to wait
                // LeaseDuration time first.
                //
                // In the default scaffold provided, the program ends immediately after
                // the manager stops, so would be fine to enable this option. However,
                // if you are doing or is intended to do any operation such as perform cleanups
                // after the manager stops then its usage might be unsafe.
                // LeaderElectionReleaseOnCancel: true,

如果想监听固定的namespace信息，可以在Reconcile内实现。