Can't save file on EC2 created by elastic beanstalk

Hello.

Does this mean that the files included in the application bundle will disappear?
https://docs.aws.amazon.com/elasticbeanstalk/latest/dg/applications-sourcebundle.html

Elastic Beanstalk instances are ephemeral - they can be replaced during deployments and other changes. You should never save files outside of the application bundles to them.

You should use other forms of persistent storage. To learn how to persist your data in Elastic Beanstalk - please read the section "Persistent Storage" in the Elastic Beanstalk Design Considerations documentation.