What do I do if I need to use linux cron and execute command in one of my containers? When I started to google this, I found 2 solutions right away, but both seemed quite bad: Bad option 1: Build custom crontab image, copy crontab file inside, and then run a command towards other container. - I will need to rebuild this image every time I need to change my cron command or add a new one. Also it will be quite problematic to make calls from my cron container to other containers, where I really need command to run. Problem with this approach is Bad option 2: Modify container to run crontab. - my container will have to run 2 commands (crontab + whatever container used to run) - this contradicts philosophy of docker, each container is supposed to be responsible only for 1 task. Problem with this approach is Good option: Run cron on host machine where I start my docker containers. I can do it using command like this, right in crontab: * * * * * docker exec -t {containerID} {command} >> /dev/ >& null 2 1 For example: * * * * * docker exec -t {containerID} {command} >> /dev/null 2>&1

For example:
* * * * * docker exec -t $(docker ps -qf "name=docker_php_1") php artisan schedule:run >> /dev/null 2>&1 Notes: normally I would run " " - but container id will change every time I restart container, and I do not want to change crontab everytime docker exec -t <container_id> php artisan schedule:run $( ) - allows to get container id based on search by container name docker ps -qf "name=docker_php_1" $( ) - allows to get container id based on search by image name docker ps -qf "ancestor=php:7.2-fpm" - Laravel specific command to run scheduled tasks, used here just as example php artisan schedule:run

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How To Setup Cron And Docker Correctly [A How To Guide]

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