kubernetes client-go 管理 deployment
tags: client-go,Deployment
文章目录
kubernetes client-go 管理 deployment
1. deployment控制器实现流程：
2. 操作deployment查看创建
2.1 go.mod
2.2 client.go
Kubernetes Deployment【1】管理与编排入门
Kubernetes Deployment【2】原理深入详解
Kubernetes Deployment【3】管理高级技巧详解
Kubernetes Deployment【4】client-go 管理 deployment
云原生圣经
1. deployment控制器实现流程：
Deployment 控制器从 Etcd 中获取到所有携带了“app: nginx”标签的 Pod，然后统计它们的数量，这就是实际状态；
Deployment 对象的 Replicas 字段的值就是期望状态；
Deployment 控制器将两个状态做比较，然后根据比较结果，确定是创建 Pod，还是删除已有的 Pod
可以看到，一个 Kubernetes 对象的主要编排逻辑，实际上是在第三步的“对比”阶段完成的。这个操作，通常被叫作调谐（Reconcile）。这个调谐的过程，则被称作“Reconcile Loop”（调谐循环）或者“Sync Loop”（同步循环）。我们社区交流也称为“控制循环”，
2. 操作deployment查看创建
注意：
Apps/v1beta1 1.16版本以上不再支持，而是Apps/v1
deployments, err := clientset.Appv1().Deployments("").List(metav1.ListOptions{})
2.1 go.mod
module createdeployment go 1.13 require ( github.com/evanphx/json-patch v4.9.0+incompatible // indirect github.com/fsnotify/fsnotify v1.4.9 // indirect github.com/golang/groupcache v0.0.0-20191227052852-215e87163ea7 // indirect github.com/golang/protobuf v1.4.2 // indirect github.com/googleapis/gnostic v0.4.0 // indirect github.com/gregjones/httpcache v0.0.0-20190611155906-901d90724c79 // indirect github.com/imdario/mergo v0.3.11 // indirect github.com/json-iterator/go v1.1.10 // indirect github.com/pkg/errors v0.9.1 // indirect golang.org/x/net v0.0.0-20200707034311-ab3426394381 // indirect golang.org/x/sys v0.0.0-20200622214017-ed371f2e16b4 // indirect golang.org/x/text v0.3.3 // indirect golang.org/x/time v0.0.0-20200630173020-3af7569d3a1e // indirect google.golang.org/protobuf v1.24.0 // indirect k8s.io/apimachinery v0.17.0 k8s.io/client-go v0.17.0 k8s.io/gengo v0.0.0-20200413195148-3a45101e95ac // indirect k8s.io/klog/v2 v2.2.0 // indirect k8s.io/utils v0.0.0-20201110183641-67b214c5f920 // indirect sigs.k8s.io/structured-merge-diff/v4 v4.0.1 // indirect )
2.2 client.go
package main import ( "k8s.io/client-go/tools/clientcmd" "k8s.io/client-go/kubernetes" appsv1 "k8s.io/api/apps/v1" metav1 "k8s.io/apimachinery/pkg/apis/meta/v1" apiv1 "k8s.io/api/core/v1" "k8s.io/client-go/kubernetes/typed/apps/v1" "flag" "fmt" "encoding/json" ) func main() { //kubelet.kubeconfig 是文件对应地址 kubeconfig := flag.String("kubeconfig", "/root/.kube/config", "(optional) absolute path to the kubeconfig file") flag.Parse() // 解析到config config, err := clientcmd.BuildConfigFromFlags("", *kubeconfig) if err != nil { panic(err.Error()) } // 创建连接 clientset, err := kubernetes.NewForConfig(config) if err != nil { panic(err.Error()) } deploymentsClient := clientset.AppsV1().Deployments("default") //创建deployment createDeployment(deploymentsClient) //监听deployment startWatchDeployment(deploymentsClient) } //监听Deployment变化 func startWatchDeployment(deploymentsClient v1.DeploymentInterface) { w, _ := deploymentsClient.Watch(metav1.ListOptions{}) for { select { case e, _ := <-w.ResultChan(): fmt.Println(e.Type, e.Object) } } } //创建deployemnt，需要谨慎按照部署的k8s版本来使用api接口 func createDeployment(deploymentsClient v1.DeploymentInterface) { var r apiv1.ResourceRequirements //r = new(*apiv1.ResourceRequirements) //资源分配会遇到无法设置值的问题，故采用json反解析 j := `{"limits": {"cpu":"200m", "memory": "1Gi"}, "requests": {"cpu":"200m", "memory": "1Gi"}}` json.Unmarshal([]byte(j), &r) deployment := &appsv1.Deployment{ ObjectMeta: metav1.ObjectMeta{ Name: "nginx", Labels: map[string]string{ "app": "nginx", }, }, Spec: appsv1.DeploymentSpec{ Replicas: int32Ptr2(1), Selector: &metav1.LabelSelector{ MatchLabels: map[string]string{ "app": "nginx", }, }, Template: apiv1.PodTemplateSpec{ ObjectMeta: metav1.ObjectMeta{ Labels: map[string]string{ "app": "nginx", }, }, Spec: apiv1.PodSpec{ Containers: []apiv1.Container{ { Name: "nginx", Image: "nginx:1.13.5-alpine", Resources: r, ImagePullPolicy: "IfNotPresent", Ports: []apiv1.ContainerPort{ { Name: "http", Protocol: apiv1.ProtocolTCP, ContainerPort: 80, }, }, }, }, }, }, }, } fmt.Println("Creating deployment...") result, err := deploymentsClient.Create(deployment) if err != nil { panic(err) } fmt.Printf("Created deployment %s.\n", result.GetObjectMeta().GetName()) } func int32Ptr2(i int32) *int32 { return &i }
参考资料：
https://godoc.org/k8s.io/client-go/kubernetes#Clientset
https://godoc.org/k8s.io/client-go/kubernetes/typed/core/v1
https://github.com/openshift/origin/blob/master/vendor/k8s.io/kubernetes/pkg/kubelet/kubelet_pods.go
https://www.bookstack.cn/read/huweihuang-kubernetes-notes/develop-client-go.md
