Kubernetes scheduling answers whether a Pod can fit a node under the applicable resource requests and placement constraints. It does not simply look at a current CPU utilization chart and place work wherever the line is low. Requests provide accounting inputs for future demand; actual usage is a separate observation. Diagnose both before deciding that an idle-looking cluster has capacity for a particular Pod. ...
A CronJob does not run your work; it creates a Job, and the Job creates a pod. When the pod finishes, neither the Job nor the pod disappears. The pod is kept on purpose so you can still read its logs after the fact, and the Job is kept so you can still read its status. ...
Cron accepts schedules from more than one kind of table. A user crontab belongs to one account, while system tables can name the account for each entry. Copying a line between them without adjusting its fields changes what cron interprets as the command. Identify the table format before debugging an apparently correct five-field calendar expression. ...