What are the trade-offs between running cron within a Docker container vs. running a Docker container from the host machine's cron?

Question

I have a batch job in a Docker container that I want to run every day at 8:30am. What should I consider when deciding to either:

1. Run the container from the host machine's crontab.
2. Leave the container running, and set up cron within the container to handle the scheduling.

Thanks!

Answer 1

Advantages of 1:

• Cron usually always starts on boot so you don't have to worry about starting your container when the host restarts
• Logging occurs on your host
• Easier to manage cron jobs because they're in one place

Disadvantages:

• Have to maintain versioning of the crontab and scripts

Advantages of 2:

• Self-contained
• Reproducible containers with versionable Dockerfiles

Disadvantages:

• Have to start the container on boot and make sure it stays running
• Each container has it's own logs, so if you use a central logging server this makes it complicated
• The container needs to be rebuilt on any changes to the cron job.