Managing crons with SaltStack

SaltStack has a pretty cool feature where you can manage your systems' crontabs from a central location. You can keep them in state SLS files and look them up via salt cron exectuion module. With a little bit of extra work, you can also keep the crons in pillars and feed them to your systems (that's something that I will certainly have to experiment with that later on). Even with base functionality, this is a pretty cool thing that should help you with truly automating your environment to the point where you will rarely have to log into a server to perform management duties.

Let's set up a basic crontab in Salt and distribute it to one of our minions just to get a basic idea how this all works.

Create a directory for your cron and an empty cron SLS file:

mkdir /srv/salt/states/cron
cd /srv/salt/states/cron
vim testcronjob.sls

Add the following to your testcronjob.sls file:

bash /opt/scripts/randomscript.sh:
- cron.present:
- user: root
- minute: '*/2'

This will execute bash /opt/scripts/randomscript.sh command every 2 minutes. You can also specify standard UNIX timing values via:

- minute: 0
- hour: 12
- daymonth: 6
- month: 4
- dayweek: 4

By default, if you don't specify a timing value, Salt will implement * for each value in the schedule.

You can implement the cron via:

salt 'testmachine01' state.sls cron.testcronjob

And you can view it by:

salt 'testmachine01' cron.list_tab root

You can find more information about managing crontabs in Salt below:

Salt cron state module:

http://docs.saltstack.com/en/latest/ref/states/all/salt.states.cron.html

Salt cron execution module:

http://docs.saltstack.com/en/latest/ref/modules/all/salt.modules.cron.html

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