The following procedure adds a cron job that executes at the same moment to all the EC2 instances in your Elastic Beanstalk environment.

Note: If you have a period task that requires execution on only one instance, consider using worker tier periodic tasks instead.

Create the .ebextensions directory structure

Create a directory named “.ebextensions” in the Elastic Beanstalk application zip file. For the purposes of the following example, the Elastic Beanstalk application zip file is named “myapp.zip”, and the configuration file is named “cronjob.config”.

Note: You can name the configuration file anything you like, but if there are multiple configuration files in the .ebextensions directory, they are executed in alphabetical order.

The below example illustrates the structure of the .ebextensions directory and cronjob.config file in the application zip file: