101 lines
5.5 KiB
Markdown
101 lines
5.5 KiB
Markdown
---
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vssueId: 151
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layout: LearningLayout
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description: Kubernetes中的Job对象将创建一个或多个Pod_并确保指定数量的Pod可以成功执行到进程正常结束_当Job创建的 Pod执行成功并正常结束时_Job将记录成功结束的Pod数量_当成功结束的Pod达到指定的数量时_Job将完成执行
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meta:
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- name: keywords
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content: Kubernetes教程,K8S教程,K8S培训,Kubernetes Job
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---
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# 控制器 - Job <Badge type="warning">Kuboard 正在计划中</Badge>
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<AdSenseTitle>
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> 参考文档： [Jobs - Run to Completion](https://kubernetes.io/docs/concepts/workloads/controllers/jobs-run-to-completion/)
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</AdSenseTitle>
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Kubernetes中的 Job 对象将创建一个或多个 Pod，并确保指定数量的 Pod 可以成功执行到进程正常结束：
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* 当 Job 创建的 Pod 执行成功并正常结束时，Job 将记录成功结束的 Pod 数量
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* 当成功结束的 Pod 达到指定的数量时，Job 将完成执行
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* 删除 Job 对象时，将清理掉由 Job 创建的 Pod
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一个简单的例子是：创建一个 Job 对象用来确保一个 Pod 的成功执行并结束。在第一个 Pod 执行失败或者被删除（例如，节点硬件故障或机器重启）的情况下，该 Job 对象将创建一个新的 Pod 以重新执行。
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当然，您也可以使用 Job 对象并行执行多个 Pod。
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## 运行一个Job的例子
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在下面这个 Job 的例子中，Pod 执行了一个跟 π 相关的计算，并打印出最终结果，该计算大约需要 10 秒钟执行结束。
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<<< @/.vuepress/public/statics/learning/job/job.yaml
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* 执行如下命令创建该对象：
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``` sh
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kubectl apply -f https://kuboard.cn/statics/learning/job/job.yaml
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```
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* 执行命令查看创建结果
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``` sh
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kubectl describe jobs/pi
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```
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输出结果如下
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```
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Name: pi
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Namespace: default
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Selector: controller-uid=b1db589a-2c8d-11e6-b324-0209dc45a495
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Labels: controller-uid=b1db589a-2c8d-11e6-b324-0209dc45a495
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job-name=pi
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Annotations: <none>
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Parallelism: 1
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Completions: 1
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Start Time: Tue, 07 Jun 2016 10:56:16 +0200
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Pods Statuses: 0 Running / 1 Succeeded / 0 Failed
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Pod Template:
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Labels: controller-uid=b1db589a-2c8d-11e6-b324-0209dc45a495
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job-name=pi
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Containers:
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pi:
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Image: perl
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Port:
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Command:
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perl
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-Mbignum=bpi
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-wle
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print bpi(2000)
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Environment: <none>
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Mounts: <none>
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Volumes: <none>
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Events:
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FirstSeen LastSeen Count From SubobjectPath Type Reason Message
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--------- -------- ----- ---- ------------- -------- ------ -------
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1m 1m 1 {job-controller } Normal SuccessfulCreate Created pod: pi-dtn4q
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```
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* 执行以下命令可查看所有结束的 Pod
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``` sh
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kubectl get pods
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```
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* 执行以下命令可获得该 Job 所有 Pod 的名字：
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``` sh
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pods=$(kubectl get pods --selector=job-name=pi --output=jsonpath='{.items[*].metadata.name}')
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echo $pods
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```
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输出结果如下
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```
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pi-aiw0a
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```
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在这个命令中：
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* selector 与 Job 定义中的 selector 相同
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* `--output=jsonpath` 选项指定了一个表达式，该表达式从返回结果列表中的每一个 Pod 的信息中定位出 `name` 字段的取值
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* 执行以下命令可查看 Pod 的日志：
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``` sh
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kubectl logs $pods
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```
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输出结果如下：
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```
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3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679821480865132823066470938446095505822317253594081284811174502841027019385211055596446229489549303819644288109756659334461284756482337867831652712019091456485669234603486104543266482133936072602491412737245870066063155881748815209209628292540917153643678925903600113305305488204665213841469519415116094330572703657595919530921861173819326117931051185480744623799627495673518857527248912279381830119491298336733624406566430860213949463952247371907021798609437027705392171762931767523846748184676694051320005681271452635608277857713427577896091736371787214684409012249534301465495853710507922796892589235420199561121290219608640344181598136297747713099605187072113499999983729780499510597317328160963185950244594553469083026425223082533446850352619311881710100031378387528865875332083814206171776691473035982534904287554687311595628638823537875937519577818577805321712268066130019278766111959092164201989380952572010654858632788659361533818279682303019520353018529689957736225994138912497217752834791315155748572424541506959508295331168617278558890750983817546374649393192550604009277016711390098488240128583616035637076601047101819429555961989467678374494482553797747268471040475346462080466842590694912933136770289891521047521620569660240580381501935112533824300355876402474964732639141992726042699227967823547816360093417216412199245863150302861829745557067498385054945885869269956909272107975093029553211653449872027559602364806654991198818347977535663698074265425278625518184175746728909777727938000816470600161452491921732172147723501414419735685481613611573525521334757418494684385233239073941433345477624168625189835694855620992192221842725502542568876717904946016534668049886272327917860857843838279679766814541009538837863609506800642251252051173929848960841284886269456042419652850222106611863067442786220391949450471237137869609563643719172874677646575739624138908658326459958133904780275901
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```
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