7.6 创建你的第一个Operator：从零开始的实战演练

7.6 创建你的第一个Operator：从零开始的实战演练

在前面的课程中，我们学习了Operator的核心概念、架构设计和技术组件。现在，让我们通过实战演练，从零开始创建一个完整的Operator。通过这个实践过程，你将掌握Operator开发的完整流程，并能够独立开发自己的Operator。

环境准备

开发环境要求

在开始开发Operator之前，需要确保开发环境满足以下要求：

安装必要工具

# 安装Go语言环境（1.19+版本）wgethttps://go.dev/dl/go1.19.2.linux-amd64.tar.gzsudotar-C/usr/local-xzfgo1.19.2.linux-amd64.tar.gzexportPATH=$PATH:/usr/local/go/bin# 验证Go安装go version# 安装Kubebuilder（推荐方式）curl-L-okubebuilder https://go.kubebuilder.io/dl/latest/$(goenvGOOS)/$(goenvGOARCH)chmod+x kubebuildersudomvkubebuilder /usr/local/bin/# 或者安装Operator SDKcurl-LOhttps://github.com/operator-framework/operator-sdk/releases/download/v1.27.0/operator-sdk_linux_amd64chmod+x operator-sdk_linux_amd64sudomvoperator-sdk_linux_amd64 /usr/local/bin/operator-sdk# 安装kubectlcurl-LO"https://dl.k8s.io/release/$(curl-L-shttps://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl"chmod+x kubectlsudomvkubectl /usr/local/bin/# 安装Dockersudoapt-getupdatesudoapt-getinstalldocker.io

准备Kubernetes集群

# 使用kind创建本地集群（用于开发测试）curl-Lo./kind https://kind.sigs.k8s.io/dl/v0.17.0/kind-linux-amd64chmod+x ./kindsudomv./kind /usr/local/bin/kind# 创建集群kind create cluster# 验证集群kubectl cluster-info kubectl get nodes

项目初始化

使用Kubebuilder初始化项目

# 创建项目目录mkdirvisitor-operatorcdvisitor-operator# 初始化项目kubebuilder init--domainexample.com--repogithub.com/example/visitor-operator# 创建APIkubebuilder create api--groupvisitor--versionv1--kindVisitorApp--resource--controller# 生成CRD和RBAC清单makemanifests

项目结构分析

生成的项目结构如下：

visitor-operator/ ├── api/ │ └── v1/ │ ├── groupversion_info.go │ ├── visitorapp_types.go │ └── zz_generated.deepcopy.go ├── config/ │ ├── crd/ │ │ ├── kustomization.yaml │ │ ├── bases/ │ │ └── patches/ │ ├── default/ │ ├── manager/ │ ├── rbac/ │ └── samples/ ├── controllers/ │ ├── suite_test.go │ └── visitorapp_controller.go ├── hack/ │ └── boilerplate.go.txt ├── Dockerfile ├── Makefile ├── PROJECT └── main.go

定义自定义资源

修改CRD定义

// api/v1/visitorapp_types.gopackagev1import(metav1"k8s.io/apimachinery/pkg/apis/meta/v1")// VisitorAppSpec defines the desired state of VisitorApptypeVisitorAppSpecstruct{// Replicas is the desired number of replicasReplicasint32`json:"replicas,omitempty"`// Image is the container image to useImagestring`json:"image,omitempty"`// Port is the container port to exposePortint32`json:"port,omitempty"`// VisitorMessage is the message to display to visitorsVisitorMessagestring`json:"visitorMessage,omitempty"`// Resources defines the resource requirementsResources Resources`json:"resources,omitempty"`}// Resources defines the resource requirements for the applicationtypeResourcesstruct{Requests ResourceList`json:"requests,omitempty"`Limits ResourceList`json:"limits,omitempty"`}// ResourceList defines a list of resourcestypeResourceListstruct{CPUstring`json:"cpu,omitempty"`Memorystring`json:"memory,omitempty"`}// VisitorAppStatus defines the observed state of VisitorApptypeVisitorAppStatusstruct{// Replicas is the number of actual replicasReplicasint32`json:"replicas"`// ReadyReplicas is the number of ready replicasReadyReplicasint32`json:"readyReplicas"`// Phase is the current phase of the applicationPhase VisitorAppPhase`json:"phase,omitempty"`// Conditions represent the latest available observations of an object's stateConditions[]metav1.Condition`json:"conditions,omitempty"`}// VisitorAppPhase is a label for the condition of a VisitorApp at the current timetypeVisitorAppPhasestringconst(// VisitorAppPhasePending means the VisitorApp is being createdVisitorAppPhasePending VisitorAppPhase="Pending"// VisitorAppPhaseRunning means the VisitorApp is runningVisitorAppPhaseRunning VisitorAppPhase="Running"// VisitorAppPhaseFailed means the VisitorApp has failedVisitorAppPhaseFailed VisitorAppPhase="Failed")//+kubebuilder:object:root=true//+kubebuilder:subresource:status//+kubebuilder:printcolumn:name="Replicas",type="integer",JSONPath=".spec.replicas"//+kubebuilder:printcolumn:name="Ready",type="integer",JSONPath=".status.readyReplicas"//+kubebuilder:printcolumn:name="Phase",type="string",JSONPath=".status.phase"//+kubebuilder:printcolumn:name="Age",type="date",JSONPath=".metadata.creationTimestamp"// VisitorApp is the Schema for the visitorapps APItypeVisitorAppstruct{metav1.TypeMeta`json:",inline"`metav1.ObjectMeta`json:"metadata,omitempty"`Spec VisitorAppSpec`json:"spec,omitempty"`Status VisitorAppStatus`json:"status,omitempty"`}//+kubebuilder:object:root=true// VisitorAppList contains a list of VisitorApptypeVisitorAppListstruct{metav1.TypeMeta`json:",inline"`metav1.ListMeta`json:"metadata,omitempty"`Items[]VisitorApp`json:"items"`}funcinit(){SchemeBuilder.Register(&VisitorApp{},&VisitorAppList{})}

生成代码和清单

# 生成DeepCopy方法makegenerate# 生成CRD和RBAC清单makemanifests# 查看生成的CRDcatconfig/crd/bases/visitor.example.com_visitorapps.yaml

实现Controller逻辑

修改Controller实现

// controllers/visitorapp_controller.gopackagecontrollersimport("context""fmt""time"appsv1"k8s.io/api/apps/v1"corev1"k8s.io/api/core/v1""k8s.io/apimachinery/pkg/api/errors""k8s.io/apimachinery/pkg/api/resource"metav1"k8s.io/apimachinery/pkg/apis/meta/v1""k8s.io/apimachinery/pkg/runtime""k8s.io/apimachinery/pkg/types""k8s.io/apimachinery/pkg/util/intstr"ctrl"sigs.k8s.io/controller-runtime""sigs.k8s.io/controller-runtime/pkg/client""sigs.k8s.io/controller-runtime/pkg/controller/controllerutil""sigs.k8s.io/controller-runtime/pkg/log"visitorv1"github.com/example/visitor-operator/api/v1")// VisitorAppReconciler reconciles a VisitorApp objecttypeVisitorAppReconcilerstruct{client.Client Scheme*runtime.Scheme}//+kubebuilder:rbac:groups=visitor.example.com,resources=visitorapps,verbs=get;list;watch;create;update;patch;delete//+kubebuilder:rbac:groups=visitor.example.com,resources=visitorapps/status,verbs=get;update;patch//+kubebuilder:rbac:groups=visitor.example.com,resources=visitorapps/finalizers,verbs=update//+kubebuilder:rbac:groups=apps,resources=deployments,verbs=get;list;watch;create;update;patch;delete//+kubebuilder:rbac:groups=core,resources=services,verbs=get;list;watch;create;update;patch;delete//+kubebuilder:rbac:groups=core,resources=configmaps,verbs=get;list;watch;create;update;patch;delete//+kubebuilder:rbac:groups=core,resources=events,verbs=create;patch// Reconcile is part of the main kubernetes reconciliation loop which aims to// move the current state of the cluster closer to the desired state.func(r*VisitorAppReconciler)Reconcile(ctx context.Context,req ctrl.Request)(ctrl.Result,error){log:=log.FromContext(ctx)log.Info("Reconciling VisitorApp","VisitorApp",req.NamespacedName)// 获取VisitorApp实例visitorApp:=&visitorv1.VisitorApp{}iferr:=r.Get(ctx,req.NamespacedName,visitorApp);err!=nil{// 如果资源不存在，可能是被删除了returnctrl.Result{},client.IgnoreNotFound(err)}// 执行协调逻辑result,err:=r.reconcileVisitorApp(ctx,visitorApp)iferr!=nil{log.Error(err,"Failed to reconcile VisitorApp")returnresult,err}returnresult,nil}func(r*VisitorAppReconciler)reconcileVisitorApp(ctx context.Context,visitorApp*visitorv1.VisitorApp)(ctrl.Result,error){log:=log.FromContext(ctx)// 1. 确保ConfigMap存在iferr:=r.ensureConfigMap(ctx,visitorApp);err!=nil{returnctrl