Kuberun should honour -bg (background) option

[bentsherman]

New feature

nextflow kuberun creates a pod spec, launches it on a k8s cluster, and streams the log output of the pod. It would be convenient in some cases for kuberun to simply launch the pod and then exit. That is, since kuberun creates a "head node" on the k8s cluster which pefrorms the rest of the workflow, it is not necessary to have the local machine tethered to the entire process.

Usage scenario

Maybe I want to start the workflow and then turn off my machine for a week while the workflow proceeds on the k8s cluster.

Suggest implementation

Add an option to kuberun (something like --standalone or --batch) which simply causes kuberun to exit after submitting the pod.

If the user then wants to view the pod output, they can do so with kubectl logs <pod-name>.

[pditommaso]

Make sense. Actually, there's already a background option. When used on the kuberun command it should behave accordingly.

[bentsherman]

Not quite the same, actually. With this option nextflow is still running on the local machine such that the k8s job would be disrupted if the local machine turns off. The local process must exit after submitting the controller pod, not merely run in the background.

[pditommaso]

Indeed. What I'm saying is that when -bg is specified on kuberun it should do what you are proposing.