How to run a cron job inside a docker container?

Question

I am trying to run a cronjob inside a docker container that invokes a shell script.

Yesterday I have been searching all over the web and stack overflow, but I could

Answer 1

Here's my docker-compose based solution:

  cron:
    image: alpine:3.10
    command: crond -f -d 8
    depends_on:
      - servicename
    volumes:
      - './conf/cron:/etc/crontabs/root:z'
    restart: unless-stopped

the lines with cron entries are on the ./conf/cron file.

Note: this won't run commands that aren't on the alpine image.