使用Kubernetes的java-client实现Deployment的部署及更新操作
1. 背景介绍
需求: 针对多种协议SDK构造探针,测试公司接入机服务状况(每一个探针应对单一接入机,接入机数量可能会动态变化).
难点: 大多数协议SDK均不支持多实例运行,且部分SDK通过生成文件保存内部状态;各协议SDK处于迭代状态,不能对其进行魔改.
分析:
(1) 基于以上原因,无法选择多线程或者多进程,在单一物理机或容器内完成探针相应功能;
(2) 尝试通过Kubernetes部署探针容器,通过容器完成不同协议SDK的进程隔离乃至文件隔离;
(3) 通过Deployment设置容器环境参数的方式,给不同容器设置对应的启动参数;
(4) Kubernetes控制程序通过Apollo动态获取配置,更新相应协议的Deployment,从而更新相关容器镜像.
2. 依赖设置
pom文件中添加kubernetes以及apollo依赖:
<dependency>
<groupId>io.kubernetes</groupId>
<artifactId>client-java</artifactId>
<version>4.0.0</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>com.ctrip.framework.apollo</groupId>
<artifactId>apollo-client</artifactId>
<version>1.1.0</version>
</dependency>
3. 部署Deployment
3.1 获取api client
注意,此处我们使用ExtensionsV1beta1Api ,对应api version: extensions/v1beta1.
在实际操作中,可以通过kubectl version获取api server支持的版本.
ApiClient client;
try {
client = Config.defaultClient();
} catch (IOException ex) {
log.error("get k8s default client failed, error: [{}]", ex.getMessage());
throw new UserException(AppStatus.INTERNAL_SERVER_ERROR, "can not get k8s default client.");
}
Configuration.setDefaultApiClient(client);
ExtensionsV1beta1Api api = new ExtensionsV1beta1Api(client);
3.2 创建Deployment
Deployment创建需要设置如下内容:
api version;kind;meta data;spec info.
不熟悉以上元素的,可以查阅官方文档,或者通过Kubernetes inAction一书了解.
ExtensionsV1beta1Deployment edpDeployment = new ExtensionsV1beta1Deployment();
edpDeployment.setApiVersion("extensions/v1beta1");
edpDeployment.setKind("Deployment");
edpDeployment.setMetadata(createDeploymentMeta(namespace, ProtocolType.EDP, config));
edpDeployment.setSpec(createDeploymentSpec(ProtocolType.EDP, config));
try {
appsV1Api.createNamespacedDeployment(Common.INSPECTOR_NAMESPACE, edpDeployment, false, null, null);
} catch (ApiException e) {
log.error(e.getMessage());
}
至此,可以通过kubectl相关命令查看Deployment的创建情况.
4. 更新Deployment
Deployment的更新操作比较晦涩,需要先构建ArrayList<JsonObject>存放更新操作以及相应数值(此处使用Gson),进而调用相应接口完成操作.
/**
* 构造Deployment的更新信息(json格式,需要指定操作类型,更新元素路径,以及更新后的数值)
* 此处,仅示范如何更新pod中第一个容器(filebeta)的镜像ID
* @return json信息
*/
public ArrayList<JsonObject> getInspectorImagePatchElements() {
// k8s java-client官方示例使用Gson
Gson gson = new Gson();
ArrayList<JsonObject> result = new ArrayList<>();
// 更新Deployment中的filebeta容器镜像ID
DeploymentPatchJson patchJson = new DeploymentPatchJson("replace",
"/spec/template/spec/containers/0/image", appConfig.geFilebetaImageId());
result.add((gson.fromJson(gson.toJson(patchJson), JsonElement.class)).getAsJsonObject());
return result;
}
/**
* 更新指定的Deployment
*
*/
public void patchCurrentDeployment(ExtensionsV1beta1Api api, ExtensionsV1beta1Deployment deployment) {
ArrayList<JsonObject> patchElements = inspectorService.getInspectorImagePatchElements();
try {
api.patchNamespacedDeployment(deployment.getMetadata().getName(),
deployment.getMetadata().getNamespace(), patchElements, "true", null);
} catch (ApiException e) {
log.error("patch deployment failed, error: [{}]", e.getMessage());
}
}
5. 手动更新Deployment
(1) kubectl仿照调用api
kubectl patch deployment your_deployment -p \
'{"spec":{"template":{"spec":{"terminationGracePeriodSeconds":31}}}}'
(2) 通过HTTP请求
curl --header "Content-Type: application/json-patch+json" \
--request PATCH \
--data '[{"op": "add", "path": "/status/capacity/example.com~1foo", "value": "5"}]' \
http://k8s-master:8080/api/v1/nodes/k8s-node-1/status
(3) kubectl设置
带*信息,请根据实际情况进行替换.
kubectl set image deployment/composer app=hub.***.com/online/composer:pro2019051602 --context=devops* -n qos*
(4) 直接编辑Deployment
kubectl edit deployment composer -n qos* --context=devops*
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