Job用來在k8s集群中批量執(zhí)行一次性任務(wù)，并提供了失敗重試機(jī)制。其載體可以是容器中的一個(gè)腳本。

下面是創(chuàng)建一個(gè)Job的具體流程的案例

創(chuàng)建一個(gè)執(zhí)行任務(wù)的鏡像

業(yè)務(wù)腳本testFunc.py

import argparse
import json

def concat(firstName, n):
    return json.dumps({'status': 200, 'msg': firstName*n})

if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument('--firstName', type=str)
    parser.add_argument('--n', type=int)
    args = parser.parse_args()
    result = concat(args.firstName, args.n)
    print(result)

Dockerfile

FROM python:3.9
WORKDIR /app
COPY testFunc.py /app
CMD ["python", "testFunc.py", "--firstName", "Tommy", "--n", "2"]

使用docker build -t lyudmilalala/job-test .創(chuàng)建本地鏡像lyudmilalala/job-test

測(cè)試鏡像

$ docker run -it --rm lyudmilalala/job-test
{"status": 200, "msg": "TommyTommy"}

通過修改啟動(dòng)命令cmd可以獲得不同結(jié)果

$ docker run -it --rm lyudmilalala/job-test python testFunc.py --firstName "Test" --n 5
{"status": 200, "msg": "TestTestTestTestTest"}

使用yaml創(chuàng)建k8s job

啟動(dòng)k8s job用的yaml配置文件testFunc.yml

使用yaml啟動(dòng)job【確保k8s集群已經(jīng)開啟】

kubectl apply -f .\testFunc.yml

一開始的任務(wù)才開始執(zhí)行，pod剛啟動(dòng)

$ kubectl get job -A
NAMESPACE   NAME       COMPLETIONS   DURATION   AGE
default     job-test   0/4           1s         1s
$ kubectl get pods -n default
NAME             READY   STATUS              RESTARTS   AGE
job-test-q9cdr   0/1     ContainerCreating   0          1s
job-test-w2lr7   0/1     ContainerCreating   0          1s
job-test-xbd8d   0/1     ContainerCreating   0          1s

過了一會(huì)兒后，pod執(zhí)行完畢，job也被標(biāo)記為完成

$ kubectl get pods -n default
NAME             READY   STATUS      RESTARTS   AGE
job-test-7vgqz   0/1     Completed   0          6s
job-test-q9cdr   0/1     Completed   0          9s
job-test-w2lr7   0/1     Completed   0          9s
job-test-xbd8d   0/1     Completed   0          9s
$ kubectl get job -A
NAMESPACE   NAME       COMPLETIONS   DURATION   AGE
default     job-test   4/4           6s         18s

查看對(duì)應(yīng)的執(zhí)行了任務(wù)的pod的log，可以看到結(jié)果

$ kubectl logs job-test-867x8 
{"status": 200, "msg": "HelenHelenHelenHelen"}

Job不會(huì)自動(dòng)刪除，因此完成后需要手動(dòng)刪除
Job使用的pod也不會(huì)自動(dòng)刪除，會(huì)在Job被手動(dòng)刪除時(shí)跟著一起刪除

kubectl delete job job-test

使用java程序創(chuàng)建k8s job

引用io.fabric8.kubernetes.client包

Java程序

import io.fabric8.kubernetes.client.Config;
import io.fabric8.kubernetes.client.ConfigBuilder;
import io.fabric8.kubernetes.client.DefaultKubernetesClient;
import io.fabric8.kubernetes.client.KubernetesClient;

public class Main {
    public static void main(String[] args) {
        // Set up config
        Config config = new ConfigBuilder()
                .withMasterUrl("https://kubernetes.docker.internal:6443/")
                .withOauthToken("my-jwt-token-in-secret")
                // .withUsername("username").withPassword("password")  if you're using basic auth
                // .withTrustCerts(false) if you want to disable certification checks
                .build();

        // Initialize client
        try (KubernetesClient client = new DefaultKubernetesClient(config)) {
            final String namespace = "default";
            final Job job = new JobBuilder()
                    .withApiVersion("batch/v1")
                    .withNewMetadata()
                    .withName("java-job-test")
//                    .withLabels()
//                    .withAnnotations()
                    .endMetadata()
                    .withNewSpec()
                    .withNewTemplate()
                    .withNewSpec()
                    .addNewContainer()
                    .withName("java-job-test-container")
                    .withImagePullPolicy("IfNotPresent")
                    .withImage("lyudmilalala/job-test")
                    .withCommand("python", "testFunc.py", "--firstName", "Alice", "--n", "3")
                    .endContainer()
                    .withRestartPolicy("Never")
                    .endSpec()
                    .endTemplate()
                    .endSpec()
                    .build();
            job.getSpec().setParallelism(3);
            job.getSpec().setCompletions(4);
            client.batch().v1().jobs().inNamespace(namespace).resource(job).create();
            // Get All pods created by the job
            PodList podList = client.pods().inNamespace(namespace).withLabel("job-name", job.getMetadata().getName()).list();
            // Wait for pod to complete
      client.pods().inNamespace(namespace).withName(podList.getItems().get(0).getMetadata().getName())
                    .waitUntilCondition(pod -> pod.getStatus().getPhase().equals("Succeeded"), 1, TimeUnit.MINUTES);

            // Print Job's log
            String joblog = client.batch().v1().jobs().inNamespace(namespace).withName("java-job-test").getLog();
            System.out.println(joblog);
        } catch (KubernetesClientException e) {
            e.printStackTrace();
        }
    }
}