java操作k8s api示例：通过java完成对kubenetes原生资源对象（pod、node、namespace、servcie、deployment）和自定义资源对象CRD的增删改查或事件监听

本文目标

基于官方kubernetes-client/java类库，实现通过java完成对kubenetes原生资源对象（pod、node、namespace、servcie、deployment）和自定义资源对象（如：cluster）的增删改查或事件监听（watch）

k8s-client-java选型

目前通过java操作k8s，开源版本共有两个：

• kubernetes-client/java
• fabric8io/kubernetes-client

kubernetes-client/java和fabric8io/kubernetes-client对比

kubernetes-client/java的使用

REST API

API 资源使用REST模式。

kube-apiserver 支持同时提供 https（默认监听在 6443 端口）和 http API（默认监听在 127.0.0.1 的 8080 端口），其中 http API 是非安全接口，不做任何认证授权机制，不建议生产环境启用。两个接口提供的 REST API 格式相同

图片来自 OpenShift Blog

1. GET /<资源名的复数格式>：获得某一类型的资源列表，例如GET /pods 返回一个Pod资源列表。
2. POST /<资源名的复数格式>：创建一个资源，该资源来自用户提供的JSON对象。
3. GET /<资源名复数格式>/<名字>：通过给出的名称（Name）获得单个资源，例如GET /pods/first 返回一个名称为“first”的Pod。
4. DELETE /<资源名复数格式>/<名字>：通过给出的名字删除单个资源，删除选项（DeleteOptions）中可以指定的优雅删除（Grace Deletion）的时间（GracePeriodSeconds），该可选项表明了从服务端接收到删除请求到资源被删除的时间间隔（单位为秒）。
5. PUT /<资源名复数格式>/<名字>：通过给出的资源名和客户端提供的JSON对象来更新或创建资源。
6. PATCH /<资源名复数格式>/<名字>：选择修改资源详细指定的域。
7. GET /watch/<资源名复数格式>：随时间变化，不断接收一连串的JSON对象，这些JSON对象记录了给定资源类别内所有资源对象的变化情况。
8. GET /watch/<资源名复数格式>/：随时间变化，不断接收一连串的JSON对象，这些JSON对象记录了某个给定资源对象的变化情况。

REST API版本说明

为了在兼容旧版本的同时不断升级新的API，Kubernetes支持多种API版本，每种API版本都有不同的API路径，例如/api/v1或 /apis/extensions/v1beta1。

Alpha级别：

• 包含alpha名称的版本（例如v1alpha1）。
• 该软件可能包含错误。启用一个功能可能会导致bug。默认情况下，功能可能会被禁用。

Beta级别：

• 包含beta名称的版本（例如v2beta3）。
• 该软件经过很好的测试。启用功能被认为是安全的。默认情况下功能是开启的。
• 大家使用过的Beta版本后，可以多给社区反馈，如果此版本在后续更新后将不会有太大变化。

Stable级别：

• 该版本名称命名方式：vX这里X是一个整数。
• Stable版本的功能特性，将出现在后续发布的软件版本中。

Alpha、Beta、RC、GA版本的区别

• Alpha：是内部测试版,一般不向外部发布,会有很多Bug.一般只有测试人员使用。
• Beta：也是测试版，这个阶段的版本会一直加入新的功能。在Alpha版之后推出。
• RC：(Release　Candidate) 顾名思义么 ! 用在软件上就是候选版本。系统平台上就是发行候选版本。RC版不会再加入新的功能了，主要着重于除错。
• GA:General Availability,正式发布的版本，在国外都是用GA来说明release版本的。

kubectl api-versions

查看 apiserver暴露的接口

kubectl api-versions

或者

curl -H’Authorization: Bearer token’ https://192.168.1.122:6443/apis –insecure

[root@fly]# kubectl api-versions
admissionregistration.k8s.io/v1beta1
apiextensions.k8s.io/v1beta1
apiregistration.k8s.io/v1beta1
apps/v1
apps/v1beta1
apps/v1beta2
authentication.istio.io/v1alpha1
authentication.k8s.io/v1
authentication.k8s.io/v1beta1
authorization.k8s.io/v1
authorization.k8s.io/v1beta1
autoscaling/v1
autoscaling/v2beta1
batch/v1
batch/v1beta1
certificates.k8s.io/v1beta1
config.istio.io/v1alpha2
events.k8s.io/v1beta1
extensions/v1beta1
networking.istio.io/v1alpha3
networking.k8s.io/v1
policy/v1beta1
rbac.authorization.k8s.io/v1
rbac.authorization.k8s.io/v1beta1
rbac.istio.io/v1alpha1
storage.k8s.io/v1
storage.k8s.io/v1beta1
v1

REST API 实例:

https://10.10.124.199:6443/apis/apps/v1/deployment

1. https ： kube-apiserver 支持同时提供https（默认监听在 6443 端口）和 http API（默认监听在 127.0.0.1 的 8080 端口），由于http api 是不会经过认证授权的，在生产环境中，为了安全性考虑，推荐是不启用。
2. 10.10.124.199 ： 该ip地址为kubernetes master 地址，在集群为高可用设置的场景下，该ip地址为 vip 地址。
3. apis ：kubernetes在这一层级只有api 与 apis ，api只有初步核心资源，包含pod，node，namespace等基本资源
4. apps ： 为api group 名，api group 是kubernetes 对资源类型特性相近的整合。
5. v1： 是作为api group version， 在新资源类型的加入到kubernetes，会经历版本变迁： v1alpha1–>v1alpha2–>….–>v1alphaN–>v1beta1–>v1beta2–>v1 。
6. deployment ： 是kubernetes 的资源名

API Object 整体划分图 (红星符号代表常用资源)

kubernetes-client/java客户端API接口识别

ApiClient初始化&认证

ApiClient client = new ClientBuilder().setBasePath("ApiServer地址").setVerifyingSsl(false).setAuthentication(new AccessTokenAuthentication("Token")).build();Configuration.setDefaultApiClient(client);

在生产环境，建议放在 程序启动前的初始化方法中

CRD资源增删改查

使用 CustomObjectsApi apiInstance = new CustomObjectsApi(); 操作

操作示例

简要描述：

集群列表接口

请求方式：

• GET

请求URL：

• /apis/{group}/{version}/{plural}

请求URL示例：

• /apis/flycloud.cn/v1/clusters

请求java示例：

        CustomObjectsApi apiInstance = new CustomObjectsApi();String group = "flycloud.cn"; String version = "v1";String plural = "clusters";String pretty = "ture";try {Object result = apiInstance.listClusterCustomObject(group,version,plural,pretty,null,null,null,null);String listCluster = JSON.toJSONString(result);System.out.println(listCluster);} catch (ApiException e) {System.err.println("Exception when calling CustomObjectsApi#listClusterCustomObject");e.printStackTrace();}

返回结果：

 {"apiVersion": "flycloud.cn/v1","items": [{"apiVersion": "flycloud.cn/v1","kind": "Cluster","metadata": {"annotations": {"name": "top"},"creationTimestamp": "2019-08-12T07:03:23Z","generation": 1.0,"labels": {"template": "platform"},"name": "top","namespace": "cluster-top","resourceVersion": "277020","selfLink": "/apis/flycloud.cn/v1/namespaces/cluster-top/clusters/top","uid": "46528941-bccf-11e9-bfeb-005056bc7cff"},"spec": {"info": {"address": "192.168.103.60","harbor": {"address": "192.168.103.65","password": "123456","port": 443.0,"protocol": "https","user": "admin"},"jenkins": {"password": "admin","type": "jenkins","username": "admin"},"mysql": {"connectionProperties": "druid.stat.mergeSql=true druid.stat.slowSqlMillis=5000","driverClass": "com.mysql.jdbc.Driver","filters": "stat","initialSize": 0.0,"logAbandoned": true,"maxActive": 100.0,"maxOpenPreparedStatements": 50.0,"maxWait": 60000.0,"minIdle": 0.0,"minPoolSize": 2.0,"password": "123456","poolPreparedStatements": false,"removeAbandoned": true,"removeAbandonedTimeout": 900.0,"type": "api-mysql","username": "root"},"network": {"networkFlag": "calico","version": 1.0},"nfs": [{"capacity": "1","ip": "192.168.103.65","name": "nfs","path": "/nfs/top","type": "nfs"}],"port": 6443.0,"prometheusPort": 30003.0,"protocol": "https","redis": {"maxTotal": 500.0,"maxWaitMillis": 15000.0,"minIdle": 10.0,"password": "123456","testOnBorrow": true,"testWhileIdle": true,"timeBetweenEvictionRunsMillis": 600000.0,"type": "api-redis"}},"template": [{"namespace": "kube-system","serviceName": "heapster","servicePort": [{"port": 80.0,"protocol": "TCP","type": "check"}],"type": "heapster"}, {"namespace": "kube-system","serviceName": "influxdb","servicePort": [{"port": 80.0,"protocol": "TCP","type": "web"}, {"port": 8086.0,"protocol": "TCP","type": "api"}],"type": "influxdb"}, {"namespace": "kube-system","serviceName": "elasticsearch-logging-v1","servicePort": [{"port": 9200.0,"protocol": "TCP","type": "web"}, {"port": 9300.0,"protocol": "TCP","type": "api"}],"type": "es"}, {"namespace": "kube-system","serviceName": "oam-api-service","servicePort": [{"port": 8081.0,"protocol": "TCP","type": "api"}],"type": "oam-api"}, {"namespace": "kube-system","serviceName": "oam-task-service","type": "oma-task"}, {"namespace": "kube-system","serviceName": "webapi-service","servicePort": [{"port": 8080.0,"protocol": "TCP","type": "api"}],"type": "webapi"}, {"namespace": "kube-system","serviceName": "webpage-service","servicePort": [{"port": 8887.0,"protocol": "TCP","type": "web"}],"type": "webpage"}, {"namespace": "kube-system","serviceName": "terminal-service","servicePort": [{"port": 8888.0,"protocol": "TCP","type": "api"}],"type": "terminal"}, {"namespace": "kube-system","serviceName": "api-mysql-service","servicePort": [{"nodePort": 30306.0,"port": 3306.0,"protocol": "TCP","type": "api"}],"type": "api-mysql"}, {"namespace": "kube-system","serviceName": "api-redis-service","servicePort": [{"nodePort": 30379.0,"port": 6379.0,"protocol": "TCP","type": "api"}],"type": "api-redis"}, {"namespace": "kube-system","serviceName": "jenkins","servicePort": [{"nodePort": 30080.0,"port": 8080.0,"protocol": "TCP","type": "api"}],"type": "jenkins"}, {"namespace": "kube-system","serviceName": "nfs-controller","type": "nfs-controller"}, {"namespace": "kube-system","serviceName": "auto-scale","type": "auto-scale"}, {"namespace": "kube-system","serviceName": "node-up-down","type": "node-up-down"}, {"namespace": "kube-system","serviceName": "calico-node","type": "calico-node"}, {"namespace": "kube-system","serviceName": "calico-kube-controller","type": "calico-cotnroller"}, {"namespace": "kube-system","serviceName": "kube-apiserver","type": "kube-apiserver"}, {"namespace": "kube-system","serviceName": "kube-controller-manager","type": "kube-controller-manager"}, {"namespace": "kube-system","serviceName": "kube-scheduler","type": "kube-scheduler"}, {"namespace": "kube-system","serviceName": "kube-proxy","type": "kube-proxy"}, {"namespace": "kube-system","serviceName": "etcd","type": "etcd"}, {"namespace": "kube-system","serviceName": "cluster-controller","type": "cluster-controller"}, {"namespace": "kube-system","serviceName": "kube-dns","servicePort": [{"port": 53.0,"protocol": "TCP","type": "check"}, {"port": 53.0,"protocol": "UDP","type": "dns"}],"type": "kube-dns"}]},"status": {"conditions": [{"status": false,"type": "Ready"}]}}, {"apiVersion": "flycloud.cn/v1","kind": "Cluster","metadata": {"annotations": {"name": "test"},"creationTimestamp": "2019-09-13T15:54:57Z","generation": 1.0,"labels": {"template": "dev"},"name": "test","namespace": "flycloud","resourceVersion": "7687403","selfLink": "/apis/flycloud.cn/v1/namespaces/flycloud/clusters/test","uid": "d5bddb21-d63e-11e9-b5a7-005056bc7cff"},"spec": {"info": {"address": "192.168.103.60","domain": [],"external": [{"labels": {"lb": "nginx"},"maxPort": 35000.0,"minPort": 33000.0,"tcpConfig": "system-expose-nginx-config-tcp","topLb": "192.168.103.61","type": "nginx","udpConfig": "system-expose-nginx-config-udp"}],"harbor": {"address": "192.168.103.59","password": "Harbor12345","port": 443.0,"protocol": "https","user": "admin"},"network": {"networkFlag": "calico","version": "1"},"nfs": [{"capacity": "1","ip": "192.168.103.65","name": "nfs","path": "/nfs/top","type": "nfs"}],"port": 6443.0,"prometheusPort": 30003.0,"protocol": "https","storages": []},"template": [{"namespace": "kube-system","serviceName": "auto-scale","type": "auto-scale"}, {"namespace": "kube-system","serviceName": "calico-kube-controller","type": "calico-cotnroller"}, {"namespace": "kube-system","serviceName": "calico-node","type": "calico-node"}, {"namespace": "kube-system","serviceName": "default-http-backend","servicePort": [{"port": 80.0,"protocol": "TCP","type": "web"}],"type": "default-http-backend"}, {"namespace": "kube-system","serviceName": "elasticsearch-logging-v1","servicePort": [{"port": 9200.0,"protocol": "TCP","type": "web"}, {"port": 9300.0,"protocol": "TCP","type": "api"}],"type": "es"}, {"namespace": "kube-system","serviceName": "etcd","type": "etcd"}, {"namespace": "kube-system","serviceName": "heapster","servicePort": [{"port": 80.0,"protocol": "TCP","type": "check"}],"type": "heapster"}, {"namespace": "kube-system","serviceName": "influxdb","servicePort": [{"port": 80.0,"protocol": "TCP","type": "web"}, {"port": 8086.0,"protocol": "TCP","type": "api"}],"type": "influxdb"}, {"namespace": "kube-system","serviceName": "kube-apiserver","type": "kube-apiserver"}, {"namespace": "kube-system","serviceName": "kube-controller-manager","type": "kube-controller-manager"}, {"namespace": "kube-system","serviceName": "kube-dns","servicePort": [{"port": 54.0,"protocol": "TCP","type": "check"}, {"port": 53.0,"protocol": "UDP","type": "dns"}],"type": "kube-dns"}, {"namespace": "kube-system","serviceName": "kube-proxy","type": "kube-proxy"}, {"namespace": "kube-system","serviceName": "kube-scheduler","type": "kube-scheduler"}, {"namespace": "kube-system","serviceName": "nfs-controller","type": "nfs-controller"}, {"namespace": "kube-system","serviceName": "nginx-controller","servicePort": [{"port": 80.0,"protocol": "TCP","type": "web"}],"type": "nginx-controller"}, {"namespace": "kube-system","serviceName": "node-up-down","type": "node-up-down"}, {"namespace": "kube-system","serviceName": "oam-api-service","servicePort": [{"port": 8081.0,"protocol": "TCP","type": "api"}],"type": "oam-api"}, {"namespace": "kube-system","serviceName": "oam-task-service","type": "oma-task"}, {"namespace": "kube-system","serviceName": "terminal-service","servicePort": [{"port": 8888.0,"protocol": "TCP","type": "api"}],"type": "terminal"}]},"status": {"conditions": [{"status": true,"type": "Ready"}]}}],"kind": "ClusterList","metadata": {"continue": "","resourceVersion": "7758294","selfLink": "/apis/flycloud.cn/v1/clusters"}
}

Namespaces增删改查

使用 CoreV1Api apiInstance = new CoreV1Api(); 操作

Node增删改查

使用 CoreV1Api apiInstance = new CoreV1Api(); 操作

Pod增删改查

使用 CoreV1Api apiInstance = new CoreV1Api(); 操作

优先级增删改查

Services增删改查

使用 CoreV1Api apiInstance = new CoreV1Api(); 操作

操作示例

@Testpublic void CoreV1ApiTest(){CoreV1Api apiInstance = new CoreV1Api();String pretty = "true"; String _continue = "_continue_example"; String fieldSelector = "fieldSelector_example"; String labelSelector = "labelSelector_example"; Integer limit = 56; String resourceVersion = "resourceVersion_example"; Integer timeoutSeconds = 56; Boolean watch = true; try {// Namespace列表V1NamespaceList result = apiInstance.listNamespace(null,pretty,null,null,null,null,null,null,null);// Node列表// V1NodeList result = apiInstance.listNode(null,pretty,null,null,null,null,null,null,null);// Service列表// V1ServiceList result = apiInstance.listNamespacedService("kube-system", null, null, null, null, null, null, null, null, null);// Service 详情// /api/v1/namespaces/kube-system/services/webapi-service// V1Service result = apiInstance.readNamespacedService("flyapi-service", "kube-system", null, null, null);System.out.println(result);// JSONGson gson=new Gson();String s = gson.toJson(result);System.out.println(s);} catch (ApiException e) {System.err.println("Exception when calling CoreV1Api#listNode");e.printStackTrace();}}

Deployment增删改查

使用 ExtensionsV1beta1Api apiInstance = new ExtensionsV1beta1Api(); 操作

参考链接：

https://github.com/kubernetes-client/java/tree/master/kubernetes
https://k8smeetup.github.io/docs/reference/client-libraries

https://glory.blog.csdn.net/article/details/101345091