docker-crontab

Alpine-based image to run scripts in crontab. It's meant to be used by binding a file containing your crontab config, as well as any scripts you may need to run.

This image is a base alpine image that adds curl and tini (as an init system for the entrypoint.sh). Additional packages can be installed at runtime, see INSTALL_PACKAGES below. Any environment variables on the container are make available to any scripts running in crontab.

Simply create a local file containing your job(s) and bind it to /crontab. See the usage example below.

By default the image will run as user 1000:1000 with the username cronuser. This can be customized by passing environment values.

Any scripts you want to run can be bind mounted to /workspace. The permissions on that path are adjusted in the entrypoint to set $CRON_USER:$CRON_GID as the owner. Note, however, that any files placed there will not have their permissions adjusted, so make sure they are correct on the host and $CRON_USER:$CRON_GID will have access to run them.

Env	Description	Default
CRON_USER	User for the cron user	cronuser
CRON_UID	UID for the cron user	1000
CRON_GID	GID for the cron user	1000
RUN_AS_ROOT	Run crons as root instead of creating a user	(empty)
INSTALL_PACKAGES	Space-separated list of additional packages to install at startup	(none)

Usage

To run the image with the default setup:

docker run -it --rm \
  -v /path/to/crontab:/crontab \
  -v /path/to/script.sh:/workspace/scripts.sh \
  git.w33ble.com/w33ble/docker-crontab

Here is an example that will override the cron user details and run the container with the same timezone as the host:

docker run -it --rm \
  -e CRON_USER=myuser \
  -e CRON_UID=1001 \
  -e CRON_GID=1001 \
  -v /etc/localtime:/etc/localtime:ro \
  -v /path/to/crontab:/crontab \
  git.w33ble.com/w33ble/docker-crontab

To run crons as root (useful for managing permissions on mounted volumes):

docker run -it --rm \
  -e RUN_AS_ROOT=1 \

To install additional alpine packages at startup:

docker run -it --rm \
  -e INSTALL_PACKAGES="rsync jq" \
  -v /path/to/crontab:/crontab \
  git.w33ble.com/w33ble/docker-crontab

Credits

The entrypoint.sh script that powers this image was adapted from theohbrothers/docker-alpine-cron.