Create a Job from existing Cronjob

[pilosus]

When working with kubectl I can easily create a Job from existing Cronjob like this:

kubectl create job --from=cronjob/<existing-cronjob-name> <your-job-name>

How can I do the same using kubernetes-client?

[roycaihw]

/cc @fabianvf

[fabianvf]

The kubectl create job --from=cronjob/* command simply pulls down the cronjob, pulls the jobTemplate out of its spec, and then creates the Job object using that template. The below code should do the same thing:

from kubernetes import client, config


job_name = 'from-cron-job'
cron_job_name = 'example'
namespace = 'default'

config.load_kube_config()
batch_v1 = client.BatchV1Api()
batch_v1beta1 = client.BatchV1beta1Api()

cron_job = batch_v1beta1.read_namespaced_cron_job(cron_job_name, namespace)

job = client.V1Job(
    api_version='batch/v1',
    kind='Job',
    metadata=client.models.V1ObjectMeta(
        name=job_name,
        # This annotation is added by kubectl, probably best to add it ourselves as well
        annotations={"cronjob.kubernetes.io/instantiate": "manual"}
    ),
    spec=cron_job.spec.job_template.spec
)

result = batch_v1.create_namespaced_job(namespace, job)
print(result)

[pilosus]

@fabianvf great, thank you!

I've seen the source code for kubectl create job --from=cronjob/*. It doesn't translate directly to kubernetes API, just as you have shown here. But wouldn't it be nice to have a shortcut in kubernetes-client, an analogue for --from=cronjob/* in client.V1Job? It could be an optional argument.

[fabianvf]

I'll defer to @roycaihw , but my impression is that this sort of higher-level functionality isn't necessarily in scope, this client occupies a space closer to client-go than to kubectl. It would be nice to have a place for these sorts of helpful functions though, I'm not sure if there is one at the moment.

[roycaihw]

https://github.com/kubernetes-client/python/tree/master/kubernetes/utils is where we put some helpful high-level functions.

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[yamikarajput546]

For creating a fresh new cronjob on GKE cluster using bearer token for authentication you can refer to this: https://techhub.go1percent.com/dashboard/projects/devops/62a1e1d8f20000af4db0c0cd

[Razihmad]

how can i add th

The kubectl create job --from=cronjob/* command simply pulls down the cronjob, pulls the jobTemplate out of its spec, and then creates the Job object using that template. The below code should do the same thing:

from kubernetes import client, config


job_name = 'from-cron-job'
cron_job_name = 'example'
namespace = 'default'

config.load_kube_config()
batch_v1 = client.BatchV1Api()
batch_v1beta1 = client.BatchV1beta1Api()

cron_job = batch_v1beta1.read_namespaced_cron_job(cron_job_name, namespace)

job = client.V1Job(
    api_version='batch/v1',
    kind='Job',
    metadata=client.models.V1ObjectMeta(
        name=job_name,
        # This annotation is added by kubectl, probably best to add it ourselves as well
        annotations={"cronjob.kubernetes.io/instantiate": "manual"}
    ),
    spec=cron_job.spec.job_template.spec
)

result = batch_v1.create_namespaced_job(namespace, job)
print(result)

how can i add time to live for this job created. after this job is finished. it should not be listed in job let say after 1 min