How starcluster decide which node to submit

[chengyangit]

Hi
I have been trying starcluster these days and having some questions regarding starcluster scheduling job:

1: I think the RAM are shared across nodes, right? That means job submitted by starcluster to a specific node can also use RAM from other node when it is insufficient. Am I understand correctly?
2: However, I noticed that ,even some node are totally free, new submitted job goes to node that is being occupied. How comes that happen?

Could you please share some explanation for these. Really appreciated!