Name: pi Namespace: default Selector: batch.kubernetes.io/ controller-uid=c9948307-e56d-4b5d-8302-ae2d7b7da6 Labels: batch.kubernetes.io/ controller-uid=c9948307-e56d-4b5d-8302-ae2d7b7da6 batch.kubernetes.io/ job-name=pi ... Annotations: batch.kubernetes.io/ job-tracking: "" Parallelism: 1 Completions: 1 Start Time: Mon, 02 Dec 2019 15:20:11 +0200 Completed At: Mon, 02 Dec 2019 15:21:16 +0200 Duration: 65s Pods Statuses: 0 Running/ 1 Succeeded/ 0 Failed Pod Template: Labels: batch.kubernetes.io/ controller-uid=c9948307-e56d-4b5d-8302-ae2d7b7da6 batch.kubernetes.io/ job-name=pi Containers: pi: Image: perl:5.34.0 Port: Host Port: Command: perl -Mbignum=bpi -wle print bpi( 2000) Environment: Mounts: Volumes: Events: Type Reason Age From Message-- ---------- ------- Normal SuccessfulCreate 21s job-controller Created pod: pi-xf9p4 Normal Completed 18s job-controller Job completed
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apiVersion: batch/v1 kind: Job metadata: annotations: batch.kubernetes.io/ job-tracking: "" ... creationTimestamp: "2022-11-10T17:53:53 Z" generation: 1 labels: batch.kubernetes.io/ controller-uid: 863452e6-270d-420e-9b94-53a54146c2 batch.kubernetes.io/ job-name: pi name: pi namespace: default resourceVersion: "4751" uid: 204fb678-040b-497f-9266-35ffa8716d specification: backoffLimit: 4 completionMode: NonIndexed conclusions: 1 parallelism: 1 selector: matchLabels: batch.kubernetes.io/ controller-uid: 863452e6-270d-420e-9b94-53a54146c2 suspend: false template: metadata: creationTimestamp: null labels: batch.kubernetes.io/ controller-uid: 863452e6-270d-420e-9b94-53a54146c2 batch.kubernetes.io/ job-name: pi spec: containers: - command: - perl - -Mbignum=bpi - -wle - print bpi( 2000) image: perl:5.34.0 imagePullPolicy: IfNotPresent name: pi resources: terminationMessagePath:/ dev/termination-log terminationMessagePolicy: File dnsPolicy: ClusterFirst restartPolicy: Never schedulerName: default-scheduler securityContext: terminationGracePeriodSeconds: 30 status: active: 1 prepared: 0 startTime: "2022-11-10T17:53:57 Z" uncountedTerminatedPods:

To see completed Pods of a Job, use kubectl get pods.

To note all the Pods that come from a Task in a machine readable form, you can utilize a command like this:

Here, the selector is the very same as the selector for the Job. The-- output=jsonpath choice specifies an expression with the name from each Pod in the returned list.

View the basic output of one of the pods:

Another method to see the logs of a Task:

The output is similar to this:

Writing a Task spec

Just like all other Kubernetes config, a Task needs apiVersion, kind, and metadata fields.

When the control aircraft produces new Pods for a Task, the.metadata.name of the Job belongs to the basis for naming those Pods. The name of a Job need to be a legitimate DNS subdomain worth, but this can produce unexpected outcomes for the Pod hostnames. For best compatibility, the name must follow the more restrictive guidelines for a DNS label. Even when the name is a DNS subdomain, the name needs to be no longer than 63 characters.

A Task likewise needs a.spec section.

Job Labels

Job labels will have batch.kubernetes.io/ prefix for job-name and controller-uid.

Pod Template

The.spec.template is the only necessary field of the.spec.

The.spec.template is a pod template. It has precisely the same schema as a Pod, other than it is embedded and does not have an apiVersion or kind.

In addition to required fields for a Pod, a pod design template in a Job must define appropriate labels (see pod selector) and a suitable restart policy.

Only a RestartPolicy equal to Never or OnFailure is permitted.

Pod selector

The.spec.selector field is optional. In almost all cases you must not specify it. See section specifying your own pod selector.

Parallel execution for Jobs

There are three primary kinds of task appropriate to run as a Task:

1. Non-parallel Jobs- usually, just one Pod is started, unless the Pod fails.
- the Job is total as quickly as its Pod ends successfully.



2. Parallel Jobs with a fixed conclusion count:- define a non-zero positive worth for.spec.completions.
- the Job represents the overall job, and is complete when there are.spec.completions successful Pods.
- when using.spec.completionMode="Indexed", each Pod gets a different index in the range 0 to.spec.completions-1.



3. Parallel Jobs with a work line:- do not specify.spec.completions, default to.spec.parallelism.
- the Pods need to collaborate amongst themselves or an external service to identify what each ought to deal with. For example, a Pod might bring a batch of approximately N items from the work queue.
- each Pod is individually capable of figuring out whether all its peers are done, and thus that the whole Job is done.
- when any Pod from the Job terminates with success, no brand-new Pods are created.
- as soon as a minimum of one Pod has actually ended with success and all Pods are ended, then the Job is finished with success.
- as soon as any Pod has exited with success, no other Pod should still be doing any work for this task or composing any output. They need to all remain in the procedure of exiting.



For a non-parallel Job, you can leave both.spec.completions and. unset. When both are unset, both are defaulted to 1.

For a fixed conclusion count Job, you need to set.spec.completions to the number of conclusions required. You can set.spec.parallelism, or leave it unset and it will default to 1.

For a work queue Job, you need to leave.spec.completions unset, and set.spec.parallelism to a non-negative integer.

For more details about how to use the various types of job, see the job patterns section.

Controlling parallelism

The requested parallelism (. spec.parallelism) can be set to any non-negative value. If it is unspecified, it defaults to 1. If it is defined as 0, then the Job is successfully stopped briefly up until it is increased.

Actual parallelism (variety of pods performing at any immediate) might be basically than requested parallelism, for a range of factors:

- For repaired conclusion count Jobs, the real number of pods running in parallel will not go beyond the number of staying completions. Higher values of.spec.parallelism are efficiently disregarded.
- For work queue Jobs, no brand-new Pods are begun after any Pod has actually succeeded-- staying Pods are enabled to finish, however.
- If the Job Controller has actually not had time to respond.
- If the Job controller stopped working to develop Pods for any reason (lack of ResourceQuota, lack of consent, etc), then there may be less pods than requested.
- The Job controller may throttle new Pod development due to excessive previous pod failures in the very same Job.
- When a Pod is with dignity closed down, it takes time to stop.
Completion mode

Jobs with set conclusion count - that is, tasks that have non null.spec.completions - can have a conclusion mode that is defined in.spec.completionMode:

NonIndexed (default): the Job is considered complete when there have been.spec.completions successfully completed Pods. In other words, each Pod conclusion is homologous to each other. Note that Jobs that have null.spec.completions are implicitly NonIndexed.


Indexed: the Pods of a Task get an associated conclusion index from 0 to.spec.completions-1. The index is offered through four mechanisms:

- The Pod annotation batch.kubernetes.io/ job-completion-index.
- The Pod label batch.kubernetes.io/ job-completion-index (for v1.28 and later). Note the feature gate PodIndexLabel must be made it possible for to utilize this label, and it is allowed by default.
- As part of the Pod hostname, following the pattern $(job-name)-$(index). When you use an Indexed Job in mix with a Service, Pods within the Job can use the deterministic hostnames to resolve each other through DNS. For more info about how to configure this, see Job with Pod-to-Pod Communication.
- From the containerized job, in the environment variable JOB_COMPLETION_INDEX.
The Job is considered complete when there is one successfully finished Pod for each index. For more info about how to utilize this mode, see Indexed Job for Parallel Processing with Static Work Assignment.
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