Use cron inside ubuntu docker container

Dockerfile

#assuming you have some script you want to run with cron

FROM ubuntu:latest
WORKDIR /app
COPY . . 
RUN apt-get update
RUN apt-get install -y cron
RUN echo "* * * * * ./app/some-script" >> /etc/cron.d/app
RUN chmod 0644 /etc/cron.d/app
RUN crontab /etc/cron.d/app
CMD ["cron", "-f"]