All nodes in a Nimbus cluster have an associated number. The number of a node is assigned at boot time by bpmaster. In turn, bpmaster determines that number by looking up the slaves MAC address in the node lines of /etc/beowulf/config.
The Master is assigned the node number -1 for consistancy.
Many commands in Nimbus call for a specification of the nodes affected by a command. The nodespec is a standardized syntax for that list which will work with all of those functions.
A nodespec element is either a single node number (5), a range of numbers seperated by a hyphen (2-6), or a status specification.
Status nodespec elements allow a command to affect all nodes in a particular status. The names are fairly self explainatory: all, allup, and allerror.
A nodespec is one or more nodespec elements seperated by a comma such as 1,2,4-10,12,23-30
beo_nss automatically provides hostname lookup for a node specification in the form n<x> where <x> is a node number. Thus, ping n1 is a valid command to ping 192.168.1.11. n-1 will translate as 192.168.1.1.
NOTE: There are a few programs (notably telnet) that bypass nss when doing a host lookup. They will not work correctly with the n<x> style node names.