本文旨在介绍kubernetes client java库的常用API

kubernetes client java api通信原理

如图所示，kubernetes中master节点跟worker节点的通信是通过API Sever进行的，而我们使用的java api与API Server的通信也是如此。java api通过与master上的6443端口上的restful接口进行通信，完成命令的分发，节点的控制，服务的管理等操作。

可以用 kubectl api-versions 命令查看目前支持的api

hj@huangji-ubuntu2004-openeuler-k8s-master:~$ kubectl api-versions
admissionregistration.k8s.io/v1
admissionregistration.k8s.io/v1beta1
apiextensions.k8s.io/v1
apiextensions.k8s.io/v1beta1
apiregistration.k8s.io/v1
apiregistration.k8s.io/v1beta1
apps/v1
authentication.k8s.io/v1
authentication.k8s.io/v1beta1
authorization.k8s.io/v1
authorization.k8s.io/v1beta1
autoscaling/v1
autoscaling/v2beta1
autoscaling/v2beta2
batch/v1
batch/v1beta1
certificates.k8s.io/v1
certificates.k8s.io/v1beta1
coordination.k8s.io/v1
coordination.k8s.io/v1beta1
discovery.k8s.io/v1beta1
events.k8s.io/v1
events.k8s.io/v1beta1
extensions/v1beta1
flowcontrol.apiserver.k8s.io/v1beta1
metrics.k8s.io/v1beta1
networking.k8s.io/v1
networking.k8s.io/v1beta1
node.k8s.io/v1
node.k8s.io/v1beta1
policy/v1beta1
rbac.authorization.k8s.io/v1
rbac.authorization.k8s.io/v1beta1
scheduling.k8s.io/v1
scheduling.k8s.io/v1beta1
storage.k8s.io/v1
storage.k8s.io/v1beta1
v1

POM依赖添加

<dependency>
    <groupId>io.kubernetes</groupId>
    <artifactId>client-java</artifactId>
    <version>18.0.0</version>
</dependency>

API查询

github.com/kubernetes-…

可以通过上面这个官方地址去查看，后缀名带有API字样的是我们可能要用到的

Api使用

ApiClient初始化&认证

@Data
@Component
public class ApiCommon {
    private CoreV1Api v1ApiInstance;
    private AutoscalingV2beta1Api autoscalingV2Api;

    private AppsV1Api appsV1Api;

    private Metrics metrics;

    private ApiClient client;

    /**
     * 该方法用于初始化API单例
     *
     * @param kubeConfigPath 传入本地可访问tokenConfig文件路径
     * @throws IOException 抛出IO异常
     * @author huangji
     */
    @Value("${custom.kube-config-path}")
    public void initApi(String kubeConfigPath) throws IOException {
        // loading the out-of-cluster config, a kubeconfig from file-system
        client =
                ClientBuilder.kubeconfig(KubeConfig.loadKubeConfig(new FileReader(kubeConfigPath))).build();

        // set the global default api-client to the in-cluster one from above
        Configuration.setDefaultApiClient(client);

        v1ApiInstance = new CoreV1Api(client);
        autoscalingV2Api = new AutoscalingV2beta1Api(client);
        appsV1Api = new AppsV1Api(client);
        metrics = new Metrics(client);
    }
}

node的增删改查接口

使用 CoreV1Api apiInstance = new CoreV1Api(); 操作

Method	HTTP request	Description
createNode	POST /api/v1/nodes	创建节点
deleteCollectionNode	DELETE /api/v1/nodes	删除多个节点
deleteNode	DELETE/api/v1/nodes/{name}	删除节点
listNode	GET /api/v1/nodes	节点列表
patchNode	PATCH/api/v1/nodes/{name}	更新节点
readNode	GET /api/v1/nodes/{name}	查询指定节点
replaceNode	PUT /api/v1/nodes/{name}	替换指定节点内容
replaceNodeStatus	PUT/api/v1/nodes/{name}/status	修改节点状态

调试代码如下，使用此代码可以打印所有node的信息

public V1PodList getPodNameList() throws ApiException, IOException {
    // file path to your KubeConfig
    String kubeConfigPath = "C:/Users/12058/Desktop/kubeconfig";
    // loading the out-of-cluster config, a kubeconfig from file-system
    ApiClient client =
            ClientBuilder.kubeconfig(KubeConfig.loadKubeConfig(new FileReader(kubeConfigPath))).build();
    // set the global default api-client to the in-cluster one from above
    Configuration.setDefaultApiClient(client);
    // the CoreV1Api loads default api-client from global configuration.
    CoreV1Api api = new CoreV1Api();
    // invokes the CoreV1Api client
    V1PodList list =
            api.listPodForAllNamespaces(null, null, null, null, null, null, null, null, null, null);
    return list;
}

deploy的增删改查接口

这个接口在2019年由ExtensionsV1beta1Api换成了AppsV1Api， 这里踩了一个坑

使用AppsV1Api apiInstance = new AppsV1Api(client); 操作

Method	HTTP request	Description
createNamespacedDeployment	POST	创建应用
deleteCollectionNamespacedDeployment	DELETE	删除多个应用
deleteNamespacedDeployment	DELETE	删除应用
listNamespacedDeployment	GET	应用列表
patchNamespacedDeployment	PATCH	更新应用
readNamespacedDeployment	GET	查询指定应用
replaceNamespacedDeployment	PUT	替换指定

调试代码如下，使用此代码可以打印所有namespace为default的信息

    public V1DeploymentList listAllDeployment() throws ApiException, IOException {
        String kubeConfigPath = "C:/Users/12058/Desktop/kubeconfig";
        // loading the out-of-cluster config, a kubeconfig from file-system
        ApiClient client =
                ClientBuilder.kubeconfig(KubeConfig.loadKubeConfig(new FileReader(kubeConfigPath))).build();
//        // set the global default api-client to the in-cluster one from above
//        Configuration.setDefaultApiClient(client);
        AppsV1Api apiInstance = new AppsV1Api(client);
        V1DeploymentList result = apiInstance.listNamespacedDeployment("default", null, null, null, null, null, null, null, null, null, null);
        return result;
    }

metrics的查询接口

metrics接口的使用依赖于metrics service，而相关服务的搭建可以参考我的文章《在kubernetes上部署metrics service》

Method	HTTP request	Description
getNodeMetrics	GET	获取节点的指标信息
getPodMetrics	GET	获取Pod的指标信息

service的增删查改接口

Method	HTTP request	Description
createNamespacedService	POST	创建service
deleteNamespacedService	DELETE	删除service
listNamespacedService	GET	查找service
replaceNamespacedService	PUT	修改service

pod的增删查改接口

Method	HTTP request	Description
createNamespacedPod	POST	创建Pod
deleteNamespacedPod	DELETE	删除Pod
listNamespacedPod	GET	查询Pod
replaceNamespacedPod	PUT	修改Pod

autoScaler的增删查改接口

Method	HTTP request	Description
createNamespacedHorizontalPodAutoscaler	POST	创建autoScaler
deleteNamespacedHorizontalPodAutoscaler	DELETE	删除autoScaler
listNamespacedHorizontalPodAutoscaler	GET	查询autoScaler
replaceNamespacedHorizontalPodAutoscaler	PUT	修改autoScaler

kubernetes client java介绍