1. 安装operator-sdk
//安装 operator-sdk
$ apt-get install operator-sdk
.....
$ operator-sdk version
operator-sdk version: v0.7.0
$ go version
go version go1.11.4 darwin/amd64
2. 创建新项目
//创建新项目目录
$ mkdir -p kubernetes-operator
//设置该目录为GOPATH路径
$ cd kubernetes-operator && exprot GOPATH=$PWD
$ mkdir -p $GOPATH/src/robotcl_operator/
$ cd $GOPATH/src/robotcl_operator/
//使用 operator-sdk 创建一个名为operator项目
$ operator-sdk new opdemo
......
//该过程需要科学上网，需要花费很长时间，请耐心等待
......
$ cd opdemo && tree -L 2
.
├── Gopkg.lock
├── Gopkg.toml
├── build
│ ├── Dockerfile
│ ├── _output
│ └── bin
├── cmd
│ └── manager
├── deploy
│ ├── crds
│ ├── operator.yaml
│ ├── role.yaml
│ ├── role_binding.yaml
│ └── service_account.yaml
├── pkg
│ ├── apis
│ └── controller
├── vendor
│ ├── cloud.google.com
│ ├── contrib.go.opencensus.io
│ ├── github.com
│ ├── go.opencensus.io
│ ├── go.uber.org
│ ├── golang.org
│ ├── google.golang.org
│ ├── gopkg.in
│ ├── k8s.io
│ └── sigs.k8s.io
└── version
└── version.go
23 directories, 8 files
3. 添加API
operator-sdk add api --api-version=app.example.com/v1 --kind=AppService
//添加API成功后，会生成源文件pkg/apis/app/v1/appservice_types.go
4. 添加Controller
operator-sdk add controller --api-version=app.example.com/v1 --kind=AppService
//添加Controller成功后，会生成源文件pkg/controller/appservice/appsrvice_controller.go
5. 自定义API
打开源文件pkg/apis/app/v1/appservice_types.go，自定义API结构体
type AppServiceSpec struct {
Size *int32 `json:"size"`
Image string `json:"image"`
Resources corev1.ResourceRequirements `json:"resources,omitempty"`
Envs []corev1.EnvVar `json:"envs,omitempty"`
Ports []corev1.ServicePort `json:"ports,omitempty"`
}
import (
appsv1 "k8s.io/api/apps/v1"
corev1 "k8s.io/api/core/v1"
appv1 "github.com/cnych/opdemo/pkg/apis/app/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
)
type AppServiceStatus struct {
appsv1.DeploymentStatus `json:",inline"`
}
完成自定义API结构体后，执行下面命令，自动生成pkg/apis/app/v1/zz_generated文件
$ operator-sdk generate k8s
6. 实现业务逻辑
打开源文件pkg/controller/appservice/appsrvice_controller.go，实现业务逻辑
func (r *ReconcileAppService) Reconcile(request reconcile.Request) (reconcile.Result, error) {
reqLogger := log.WithValues("Request.Namespace", request.Namespace, "Request.Name", request.Name)
reqLogger.Info("Reconciling AppService")
// Fetch the AppService instance
instance := &appv1.AppService{}
err := r.client.Get(context.TODO(), request.NamespacedName, instance)
if err != nil {
if errors.IsNotFound(err) {
// Request object not found, could have been deleted after reconcile request.
// Owned objects are automatically garbage collected. For additional cleanup logic use finalizers.
// Return and don't requeue
return reconcile.Result{}, nil
}
// Error reading the object - requeue the request.
return reconcile.Result{}, err
}
if instance.DeletionTimestamp != nil {
return reconcile.Result{}, err
}
// 如果不存在，则创建关联资源
// 如果存在，判断是否需要更新
// 如果需要更新，则直接更新
// 如果不需要更新，则正常返回
deploy := &appsv1.Deployment{}
if err := r.client.Get(context.TODO(), request.NamespacedName, deploy); err != nil && errors.IsNotFound(err) {
// 创建关联资源
// 1. 创建 Deploy
deploy := resources.NewDeploy(instance)
if err := r.client.Create(context.TODO(), deploy); err != nil {
return reconcile.Result{}, err
}
// 2. 创建 Service
service := resources.NewService(instance)
if err := r.client.Create(context.TODO(), service); err != nil {
return reconcile.Result{}, err
}
// 3. 关联 Annotations
data, _ := json.Marshal(instance.Spec)
if instance.Annotations != nil {
instance.Annotations["spec"] = string(data)
} else {
instance.Annotations = map[string]string{"spec": string(data)}
}
if err := r.client.Update(context.TODO(), instance); err != nil {
return reconcile.Result{}, nil
}
return reconcile.Result{}, nil
}
oldspec := appv1.AppServiceSpec{}
if err := json.Unmarshal([]byte(instance.Annotations["spec"]), oldspec); err != nil {
return reconcile.Result{}, err
}
if !reflect.DeepEqual(instance.Spec, oldspec) {
// 更新关联资源
newDeploy := resources.NewDeploy(instance)
oldDeploy := &appsv1.Deployment{}
if err := r.client.Get(context.TODO(), request.NamespacedName, oldDeploy); err != nil {
return reconcile.Result{}, err
}
oldDeploy.Spec = newDeploy.Spec
if err := r.client.Update(context.TODO(), oldDeploy); err != nil {
return reconcile.Result{}, err
}
newService := resources.NewService(instance)
oldService := &corev1.Service{}
if err := r.client.Get(context.TODO(), request.NamespacedName, oldService); err != nil {
return reconcile.Result{}, err
}
oldService.Spec = newService.Spec
if err := r.client.Update(context.TODO(), oldService); err != nil {
return reconcile.Result{}, err
}
return reconcile.Result{}, nil
}
return reconcile.Result{}, nil
}
7. 调试
$ kubectl cluster-info
Kubernetes master is running at https://ydzs-master:6443
KubeDNS is running at https://ydzs-master:6443/api/v1/namespaces/kube-system/services/kube-dns/proxy
To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.
$ kubectl create -f deploy/crds/app_v1_appservice_crd.yaml
customresourcedefinition "appservices.app.example.com" created
$ kubectl get crd
NAME AGE
appservices.app.example.com <invalid>
......
$ operator-sdk up local
INFO[0000] Running the operator locally.
INFO[0000] Using namespace default.
{"level":"info","ts":1559207203.964137,"logger":"cmd","msg":"Go Version: go1.11.4"}
{"level":"info","ts":1559207203.964192,"logger":"cmd","msg":"Go OS/Arch: darwin/amd64"}
{"level":"info","ts":1559207203.9641972,"logger":"cmd","msg":"Version of operator-sdk: v0.7.0"}
{"level":"info","ts":1559207203.965905,"logger":"leader","msg":"Trying to become the leader."}
{"level":"info","ts":1559207203.965945,"logger":"leader","msg":"Skipping leader election; not running in a cluster."}
{"level":"info","ts":1559207206.928867,"logger":"cmd","msg":"Registering Components."}
{"level":"info","ts":1559207206.929077,"logger":"kubebuilder.controller","msg":"Starting EventSource","controller":"appservice-controller","source":"kind source: /, Kind="}
{"level":"info","ts":1559207206.9292521,"logger":"kubebuilder.controller","msg":"Starting EventSource","controller":"appservice-controller","source":"kind source: /, Kind="}
{"level":"info","ts":1559207209.622659,"logger":"cmd","msg":"failed to initialize service object for metrics: OPERATOR_NAME must be set"}
{"level":"info","ts":1559207209.622693,"logger":"cmd","msg":"Starting the Cmd."}
{"level":"info","ts":1559207209.7236018,"logger":"kubebuilder.controller","msg":"Starting Controller","controller":"appservice-controller"}
{"level":"info","ts":1559207209.8284118,"logger":"kubebuilder.controller","msg":"Starting workers","controller":"appservice-controller","worker count":1}
$ kubectl create -f deploy/crds/app_v1_appservice_cr.yaml
appservice "nginx-app" created
......
{"level":"info","ts":1559207416.670523,"logger":"controller_appservice","msg":"Reconciling AppService","Request.Namespace":"default","Request.Name":"nginx-app"}
{"level":"info","ts":1559207417.004226,"logger":"controller_appservice","msg":"Reconciling AppService","Request.Namespace":"default","Request.Name":"nginx-app"}
{"level":"info","ts":1559207417.004331,"logger":"controller_appservice","msg":"Reconciling AppService","Request.Namespace":"default","Request.Name":"nginx-app"}
{"level":"info","ts":1559207418.33779,"logger":"controller_appservice","msg":"Reconciling AppService","Request.Namespace":"default","Request.Name":"nginx-app"}
{"level":"info","ts":1559207418.951193,"logger":"controller_appservice","msg":"Reconciling AppService","Request.Namespace":"default","Request.Name":"nginx-app"}
......
$ kubectl get AppService
NAME AGE
nginx-app <invalid>
$ kubectl get deploy
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
nginx-app 2 2 2 2 <invalid>
$ kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 76d
nginx-app NodePort 10.108.227.5 <none> 80:30002/TCP <invalid>
$ kubectl get pods
NAME READY STATUS RESTARTS AGE
nginx-app-76b6449498-2j82j 1/1 Running 0 <invalid>
nginx-app-76b6449498-m4h58 1/1 Running 0 <invalid>