Stop Accelerator Job Acceptance

When preparing to stop Accelerator, you may wish to stop accepting new jobs so the queued jobs can drain before the shutdown.

You can do this by implementing the vnc_policy.tcl file shown below. Since vnc_policy.tcl is interpreted inline during the nc run command, this policy refuses new jobs with an informative message. 
proc VncPolicyValidateResources { resList } {
    #
    # This policy prevents submission of new jobs with a message
    #
    VovWarning "Job not not submitted; NC closed by admin"
    exit
    return $resList; # not reached
}