dkruger/cron repository overview

⁠docker-cron

This is a simple Docker container which executes cron jobs.

If you need help writing the cron entry, checkout crontab.guru⁠.

⁠Using the image

This image really isn't as useful on its own, but is better used as a base for job-specific iamges.

For very simple cron jobs simply specify the CRONTAB_ENTRY environment variable. This is plugged directly into root's crontab spool.

docker run \
    --name some-cron \
    -e CRONTAB_ENTRY="* * * * * touch /some_file"
    dkruger/cron

More likely you'll need to modify the docker image to add additional utilities and/or tweak the crontab entry based on other environment variables. To help with that there is a entrypoint hook directory /entrypoint.d which you can place your own entrypoint files into. They will be sourced by the main ENTRYPOINT before the crontab is written. For an example, checkout dkruger/mysql-backup⁠.