Bug 210538

Summary: [feature request] limit number of running instances in crontab
Product: Base System Reporter: Mikhail Teterin <mi>
Component: binAssignee: freebsd-bugs (Nobody) <bugs>
Status: New ---    
Severity: Affects Some People    
Priority: ---    
Version: 10.2-STABLE   
Hardware: Any   
OS: Any   

Description Mikhail Teterin freebsd_committer 2016-06-24 20:37:17 UTC
Ensuring, only a single instance of a cron-job is running is a very common requirement. Currently, our cron does not offer any help there -- people must implement it in their programs/scripts. And it is usually done poorly...

anacron has a special switch -- `-s' -- which would ensure, _every_ job runs no more than one instance at any time.

I think, we can do better by expanding crontab's syntax to allow specifying the maximum number of each job's instances allowed.

I'd be happy to implement it, if the idea seems reasonable to someone with a src-commit bit...