Kubernetes fabric8 JavaAPI

一、依赖准备

<dependency>
	<groupId>io.fabric8</groupId>
	<artifactId>kubernetes-client</artifactId>
	<version>4.9.0</version>
</dependency>
下列展示代码中可能包含演示需要的依赖包，需要手动导入。全文手动原创，非其他博客及官方转载。

二、代码例子及分析

1.客户端的创建

​ Kubernetes 的资源默认是对内部是可见并可以访问的，我们可以通过以下方式去访问Kubernetes 获取我们想要的资源。

1. 对于Kubernetes 可以通过 JavaAPI 通过安全证书文件、Token或admin.conf配置外部访问
2. 同样也可以配置这些配置文件通过HTTP访问apiService访问
3. 内部也可以通过kube-proxy将内部数据暴露出来进行访问的方式。

JavaAPI访问

​ 1.1 通过安全证书访问

需要安全证书文件：apiserver-kubelet-client.crt、apiserver-kubelet-client.key、ca.crt

//创建 Config 用于创建 Client
Config config = new ConfigBuilder()
                    .withMasterUrl("ip")
                    .withCaCertData("ca.crt内容")
                    .withClientCertData("apiserver-kubelet-client.crt内容")
                    .withClientKeyData("apiserver-kubelet-client.key内容")
                    .build();
// 创建Client
KubernetesClient kubernetesClient = new DefaultKubernetesClient(config);

​ 1.2 通过配置文件访问

需要配置文件：admin.conf

config = Config.fromKubeconfig("admin.conf内容");
KubernetesClient kubernetesClient = new DefaultKubernetesClient(config);

​ 1.3 kube-proxy 配置后通过 HTTP 直接访问

首先在服务器中开启kube-proxy代理暴露8080端口：nohup kubectl proxy –port=8080 &

config = new ConfigBuilder().withMasterUrl("http://127.0.0.1:8080").build();
KubernetesClient kubernetesClient = new DefaultKubernetesClient(config);
//通过http访问k8s中的路径资源
HttpClient httpClient = HttpClientBuilder.create().build();

HttpGet httpGet = new HttpGet("http://127.0.0.1:8080/apis/devices.kubeedge.io/v1alpha1/devices");
		HttpResponse response = null;
		response = httpClient.execute(httpGet);
		HttpEntity responseEntity = response.getEntity();
		StatusLine statusLine = response.getStatusLine();
		int code = statusLine.getStatusCode();
		String result = EntityUtils.toString(responseEntity);

​ 1.4 http浏览器直接访问K8S资源的，这里暂不讲解。

2.访问操作pod、nodeSpace等基础资源

//查看Pod
MixedOperation<Pod, PodList, DoneablePod, PodResource<Pod, DoneablePod>> operation  = client.pods();
//创建Pod，获取资源处理类，在传入组装号的Pod类
NonNamespaceOperation pods =client.pods().inNamespace("default");
//配置Pod，还可以通过 pod 类组装，想要运行 这里的参数是不够的，仅作演示
Pod pod1 =new PodBuilder().withNewMetadata().withName("pod1").withNamespace("default").and().build();
pods.create(pod1);
//删除同上
pods.delete(pod1);

3.访问操作复杂管理器Deployment控制器

import io.fabric8.kubernetes.api.model.*;
import io.fabric8.kubernetes.api.model.apps.Deployment;
import io.fabric8.kubernetes.api.model.apps.DeploymentSpec;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * @author wanchen.chen
 * @ClassName K8sDeploymentConf
 * @Despriction: 用于组合 Deployment
 * @date 2020/5/17 23:40
 * @Version 1.0
 **/
public class K8sDeploymentConf {

    /**
     *
     * @param appName
     * @param image
     * @param nodeName
     * @return
     */
    public static Deployment getDepandDeployment(String appName,String image,String nodeName){
        //参数传递
        String appGroup = "appGroup";
        //参数
        Map<String,String> labels = new HashMap<String,String>();
        labels.put("app",appGroup);
        Map<String,String> nodeSelector = new HashMap<String,String>();
        nodeSelector.put("name",nodeName);
        //mataData 数据组装
        ObjectMeta mataData = new ObjectMeta();
        mataData.setName(appName);
        mataData.setLabels(labels);
        //镜像设置
        Container container = new Container();
        container.setName(appName);
        container.setImage(image);
        container.setImagePullPolicy("IfNotPresent");
        SecurityContext sc = new SecurityContext();
        sc.setPrivileged(true);
        container.setSecurityContext(sc);
        List<Container> containers = new ArrayList<>();
        containers.add(container);
        //Spec 数据组装
        //1.selector
        LabelSelector ls =new LabelSelector();
        ls.setMatchLabels(labels);
        //2.template
        ObjectMeta empMataData = new ObjectMeta();
        empMataData.setLabels(labels);
        PodSpec pods = new PodSpec();
        pods.setHostNetwork(true);
        pods.setNodeSelector(nodeSelector);
        pods.setContainers(containers);
        //2.2 组装
        PodTemplateSpec pt = new PodTemplateSpec();
        pt.setMetadata(empMataData);
        pt.setSpec(pods);
        //3.spec 组合
        DeploymentSpec ds = new DeploymentSpec();
        ds.setReplicas(1);
        ds.setSelector(ls);
        ds.setTemplate(pt);
        //Deployment 设置
        Deployment deployment =new Deployment();
        deployment.setApiVersion("apps/v1");
        deployment.setKind("Deployment");
        deployment.setMetadata(mataData);
        deployment.setSpec(ds);
        return deployment;
    }

}

Deployment操作：

//将基础Client转换为AppsAPIGroupClient，用于操作deployment
AppsAPIGroupClient oclient =client.adapt(AppsAPIGroupClient.class);
MixedOperation<Deployment, DeploymentList, DoneableDeployment, RollableScalableResource<Deployment, DoneableDeployment>> operation1
                =oclient.deployments();
//将资源转换为JSON 查看
DeploymentList deploymentList =operation1.list();
List<Deployment> deployments = deploymentList.getItems();
JSONArray jsonArray=JSON.parseArray(JSON.toJSONString(deployments));
//创建Deployment，返回创建好的Deployment文件
oclient.deployments().create(K8sDeploymentConf.getDepandDeployment("appName","image","nodeName"));
//删除同上，返回结果为boolean类型数据
oclient.deployments().delete(K8sDeploymentConf.getDepandDeployment("appName","image","nodeName"));

三、博客参考及持续更新

感谢以下博客作业的辛苦创作，参考博客：

https://www.jianshu.com/p/6bce2c2d1853

https://blog.csdn.net/Ay_Ly/article/details/90404445