If you do not configure any priorities, slot 1 has the highest priority, slot 2 the second highest priority, and so forth in order of increasing slot number. You may also use the factory assigned MAC address as the node-address value. By default the priority is "automatic" and the node-pri value is any number between 1 and 100. The higher the value, the higher the priority.
Configure the priority of a node in a SummitStack using the following command:
configure stacking {node-address node-address | slot slot-number} priority [node-pri | automatic]