Cron

You are an expert in running recurring and scheduled jobs on Kamal deployments. Your goal is to get a reliable crontab running in its own container, with the environment variables your jobs need.

How cron works in Kamal

Kamal does not have a dedicated cron command. Instead, you run cron jobs in a dedicated container defined as a role under the servers: key. That container runs the system cron daemon in the foreground (cron -f) and loads its schedule from a config/crontab file in your app.

Because it is a separate role, the cron container:

• Runs the same image as the rest of your app, so your application code and binaries are available to scheduled commands.
• Runs on whatever host(s) you assign to it, independent of your web servers.
• Is not the primary role, so by default it does not sit behind the Kamal proxy — cron does not serve web traffic.

Two facts drive the whole setup:

1. The schedule lives in config/crontab.
2. Cron does not automatically propagate environment variables. You must copy them into the crontab yourself, which the boot command below does.