Custom cron job and cron group reference
This topic helps you set up crontabs and optionally cron groups for custom modules. If your custom module needs to schedule tasks periodically, you must set up a crontab for that module. A crontab is a cron job’s configuration.
You can optionally set up a custom group, which among other things enables you to run cron jobs defined in that group independently of other cron jobs.
For a step-by-step tutorial, see Configure custom cron jobs and cron groups (tutorial).
Overview of cron
Several Magento features require at least one cron job, which schedules activities to occur in the future. A partial list of these activities follows:
- Catalog price rules
- Generating Google sitemaps
- Customer Alerts/Notifications (product price change, product back in stock)
- Private sales (Magento Commerce only)
- Automatic updating of currency rates
- All Magento e-mails (including order confirmation and transactional)
We recommend you run cron as the Magento file system owner. Do not run cron as
root; we also recommend against running cron as the web server user.
You can no longer run
dev/tools/cron.sh because the script has been removed.
Magento depends on proper cron job configuration for many important system functions, including indexing. Failure to set it up properly means Magento won’t function as expected.
UNIX systems schedule tasks to be performed by particular users using a crontab, which is a file that contains instructions to the cron daemon that tell the daemon in effect to “run this command at this time on this date”. Each user has its own crontab, and commands in any given crontab are executed as the user who owns it.
Configure cron groups
This section discusses how to optionally create a cron group for a custom module. If you don’t need to do this, continue with the next section.
A cron group is a logical group that enables you to easily run cron for more than one process at a time. Most Magento modules use the
default cron group; some modules use the
If you’re implementing cron for a custom module, it’s your choice of whether or not to use the
default group or a different group.
To configure a cron group for your module, create a
crontab.xml file in your module directory:
<your component base dir>/<vendorname>/module-<name>/etc/crontab.xml
For one group, the file should have the following contents:
||Name of the cron group. The group name doesn’t have to be unique. You can run cron for one group at a time.|
||Unique ID for this cron job.|
||Class to be instantiated (classpath).|
||Schedule in cron format. Omit this parameter if the schedule is defined in the Magento database or other storage.|
crontab.xml with two groups may look like this:
As an example, see Magento_Customer crontab.xml.
Specifying Cron group options
You may declare a new group and specify its configuration options (all of which run in store view
scope) via the
cron_groups.xml file, located in:
<your component base dir>/<vendorname>/module-<name>/etc/cron_groups.xml
Below is an example of the
||Frequency (in minutes) that schedules are written to the
||Time (in minutes) in advance that schedules are written to the
||Window of time (in minutes) that cron job must start or will be considered missed (“too late” to run).|
||Time (in minutes) that cron history is kept in the database.|
||Time (in minutes) that the record of successfully completed cron jobs are kept in the database.|
||Time (in minutes) that the record of failed cron jobs are kept in the database.|
||This feature is available only for Magento 2.1 and later.|