ergosteur/docker-cron repository overview

⁠docker-cron

A simple docker container that runs a cron invoking a shell script.

⁠how to install and use it

Copy the repository and build from the Dockerimage:

$ sudo docker build --rm -t docker-cron .

Run the docker container in the background (docker returns the id of the container):

$ sudo docker run -t -i -d docker-cron
b149b5e7306dba492558c7024809f13cfbb616cccd0f4020db61bf715f4db836

To check if it is running properly, connect to the container using the id and view the logfile. (You may have to wait 2 minutes)

$ sudo docker exec -i -t b149b5e7306dba492558c7024809f13cfbb616cccd0f4020db61bf715f4db836 /bin/bash
root@b149b5e7306d:/# cat /var/log/cron.log
Thu May 26 13:11:01 UTC 2016: executed script
Thu May 26 13:12:01 UTC 2016: executed script

The cron job is running. Now let's modify the interval and the actual job executed!

⁠how to modify

To change the interval the cron job is runned, just simply edit the crontab file. In default, the job is runned every minute.

* * * * * root /script.sh

To change the actual job performed just change the content of the script.sh file. In default, the script writes the date into a file located in /var/log/cron.log.

echo "$(date): executed script" >> /var/log/cron.log 2>&1