We have a large deployment of around a dozen servers. We'd like to use the Whenever gem but I can't figure out a way to say which machine the cron jobs should go on! We only want these jobs to run on our server that does background jobs.
Is there a way to specify this?
If you deploy the project with Capistrano and you use the default Whenever recipe, you can create a new Capistrano role
role :whenever, "192.168.1.1"
and set the role in your deploy.rb file
set :whenever_roles, "whenever"
In this way, the task will be executed only on the specified server.
whenever is preconfigured to run against the db role, so if your db role is also the background machine's role you don't have to do the 'role :whenever, "192.168.0.1"' hack. see the codes
https://github.com/javan/whenever/blob/master/lib/whenever/capistrano.rb#L2
来源：https://stackoverflow.com/questions/5065109/whenever-gem-have-cronjob-on-only-one-machine