本文主要是介绍【转载】据说这是k8s历史上的第一个operator，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
原贴地址：
据说这是k8s历史上的第一个operator_理工男Happy大叔的博客-CSDN博客_k8s operatorhttps://www.cnblogs.com/zhaowei121/p/10255540.html根据这个文章的描述，我们可以看出，k8s历史上第一个opertaor雏形应该是etcd-operator。为了了解operator的原理，我找到了etcd-operator的代码仓库，然后根据commit时间，找到了一个简单易懂的operator-demo。看完代码让我惊叹，原来operator居然几百行代码就可以完成。https://github.com/coreos/etcd-operator/.https://blog.csdn.net/LIUHUAN0520/article/details/113647187?spm=1001.2101.3001.6650.2&utm_medium=distribute.pc_relevant.none-task-blog-2%7Edefault%7ECTRLIST%7Edefault-2.nonecase&depth_1-utm_source=distribute.pc_relevant.none-task-blog-2%7Edefault%7ECTRLIST%7Edefault-2.nonecase
https://www.cnblogs.com/zhaowei121/p/10255540.html 根据这个文章的描述，我们可以看出，k8s历史上第一个opertaor雏形应该是etcd-operator。
为了了解operator的原理，我找到了etcd-operator的代码仓库，然后根据commit时间，找到了一个简单易懂的operator-demo。看完代码让我惊叹，原来operator居然几百行代码就可以完成。
https://github.com/coreos/etcd-operator/tree/0f998e0f17a810c8f1a549c76ddc69fe8711eac0。
附上代码膜拜一下，只是由于依赖的版本、仓库地址变化，现在不能直接运行起来。
package mainimport ("encoding/json""errors""flag""fmt""log""net/http""strings""github.com/pborman/uuid""k8s.io/kubernetes/pkg/api""k8s.io/kubernetes/pkg/client/restclient""k8s.io/kubernetes/pkg/client/unversioned""k8s.io/kubernetes/pkg/util/intstr"
)var masterHost stringfunc init() {flag.StringVar(&masterHost, "master", "http://127.0.0.1:8080", "usage")flag.Parse()
}type etcdClusterController struct {kclient *unversioned.Client
}func (c *etcdClusterController) Run() {eventCh, errCh := monitorNewCluster()for {select {case event := <-eventCh:c.createCluster(event)case err := <-errCh:panic(err)}}
}func (c *etcdClusterController) createCluster(event newCluster) {size := event.Sizeuuid := generateUUID()initialCluster := []string{}for i := 0; i < size; i++ {initialCluster = append(initialCluster, fmt.Sprintf("etcd%d-%s=http://etcd%d-%s:2380", i, uuid, i, uuid))}for i := 0; i < size; i++ {etcdName := fmt.Sprintf("etcd%d-%s", i, uuid)svc := makeEtcdService(etcdName, uuid)_, err := c.kclient.Services("default").Create(svc)if err != nil {panic(err)}// TODO: add and expose client portpod := makeEtcdPod(etcdName, uuid, initialCluster)_, err = c.kclient.Pods("default").Create(pod)if err != nil {panic(err)}}
}type newCluster struct {Kind string `json:"kind"`ApiVersion string `json:"apiVersion"`Metadata map[string]string `json:"metadata"`Size int `json:"size"`
}type Event struct {Type stringObject newCluster
}func monitorNewCluster() (<-chan newCluster, <-chan error) {events := make(chan newCluster)errc := make(chan error, 1)go func() {resp, err := http.Get(masterHost + "/apis/coreos.com/v1/namespaces/default/etcdclusters?watch=true")if err != nil {errc <- errreturn}if resp.StatusCode != 200 {errc <- errors.New("Invalid status code: " + resp.Status)return}log.Println("start watching...")for {decoder := json.NewDecoder(resp.Body)var ev Eventerr = decoder.Decode(&ev)if err != nil {errc <- err}event := ev.Objectlog.Println("new cluster size:", event.Size)events <- event}}()return events, errc
}func main() {c := &etcdClusterController{kclient: mustCreateClient(masterHost),}log.Println("etcd cluster controller starts running...")c.Run()
}func mustCreateClient(host string) *unversioned.Client {cfg := &restclient.Config{Host: host,QPS: 100,Burst: 100,}c, err := unversioned.New(cfg)if err != nil {panic(err)}return c
}func generateUUID() string {return uuid.New()
}func makeEtcdService(etcdName, uuid string) *api.Service {labels := map[string]string{"etcd_node": etcdName,"etcd_uuid": uuid,}svc := &api.Service{ObjectMeta: api.ObjectMeta{Name: etcdName,Labels: labels,},Spec: api.ServiceSpec{Ports: []api.ServicePort{{Name: "server",Port: 2380,TargetPort: intstr.FromInt(2380),Protocol: api.ProtocolTCP,}},Selector: labels,},}return svc
}func makeEtcdPod(etcdName, uuid string, initialCluster []string) *api.Pod {pod := &api.Pod{ObjectMeta: api.ObjectMeta{Name: etcdName,Labels: map[string]string{"app": "etcd","etcd_node": etcdName,"etcd_uuid": uuid,},},Spec: api.PodSpec{Containers: []api.Container{{Command: []string{"/usr/local/bin/etcd","--name",etcdName,"--initial-advertise-peer-urls",fmt.Sprintf("http://%s:2380", etcdName),"--listen-peer-urls","http://0.0.0.0:2380","--listen-client-urls","http://0.0.0.0:2379","--advertise-client-urls",fmt.Sprintf("http://%s:2379", etcdName),"--initial-cluster",strings.Join(initialCluster, ","),"--initial-cluster-state","new",},Name: etcdName,Image: "gcr.io/coreos-k8s-scale-testing/etcd-amd64:3.0.4",Ports: []api.ContainerPort{{Name: "server",ContainerPort: int32(2380),Protocol: api.ProtocolTCP,},},},},RestartPolicy: api.RestartPolicyNever,},}return pod
}
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