Is it possible to configure open pbs in such a way that a user can submit a maximum of 4 jobs but can only use a maximum of 4 nodes? Meaning a user can submit a maximum of 4 single node jobs or submit 2 jobs that uses 2 nodes each. At any moment the user can only use a maximum of 4 nodes.
There is no configuration to limit the user to X number of nodes or to achieve the above goal.
However, if all the user(s) jobs request -l place=excl , then this can be achieved via server and queue limits.