Known limitations
The job specification restart policy only applies to the pods, and not the job controller. However, the job controller is hard-coded to keep retrying jobs to completion.
As such, restartPolicy: Never or --restart=Never results in the same behavior as restartPolicy: OnFailure or --restart=OnFailure. That is, when a job fails it is restarted automatically until it succeeds (or is manually discarded). The policy only sets which subsystem performs the restart.
With the Never policy, the job controller performs the restart. With each attempt, the job controller increments the number of failures in the job status and creates new pods. This means that with each failed attempt, the number of pods increases.
With the OnFailure policy, kubelet performs the restart. Each attempt does not increment the number of failures in the job status. In addition, kubelet retries failed jobs starting pods on the same nodes.