kubernetes
/
website
mirror of https://github.com/kubernetes/website.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

Merge pull request #6760 from tengqm/cronjob 

Clarify CronJobs behavior
pull/6304/merge
Joseph Heck 2018-01-14 09:10:48 -08:00 committed by GitHub
parent 24d9231d91 1259684cd9
commit 01d2be3d17
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 16 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
docs/concepts/workloads/controllers/cron-jobs.md
View File

@ -123,8 +123,22 @@ A cron job creates a job object _about_ once per execution time of its schedule.
are certain circumstances where two jobs might be created, or no job might be created. We attempt to make these rare, are certain circumstances where two jobs might be created, or no job might be created. We attempt to make these rare,
but do not completely prevent them. Therefore, jobs should be _idempotent_. but do not completely prevent them. Therefore, jobs should be _idempotent_.
The job is responsible for retrying pods, parallelism among pods it creates, and determining the success or failure If `startingDeadlineSeconds` is set to a large value or left unset (the default)
of the set of pods. A cron job does not examine pods at all. and if `concurrentPolicy` is set to `AllowConcurrent`, the jobs will always run
at least once.
Jobs may fail to run if the CronJob controller is not running or broken for a
span of time from before the start time of the CronJob to start time plus
`startingDeadlineSeconds`, or if the span covers multiple start times and
`concurrencyPolicy` does not allow concurrency.
For example, suppose a cron job is set to start at exactly `08:30:00` and its
`startingDeadlineSeconds` is set to 10, if the CronJob controller happens to
be down from `08:29:00` to `08:42:00`, the job will not start.
Set a longer `startingDeadlineSeconds` if starting later is better than not
starting at all.
The job is only responsible for creating Jobs that match its schedule, and the
the Job in turn is responsible for the management of the Pods it represents.
## Writing a Cron Job Spec ## Writing a Cron Job Spec