Linux Edu Handbook

bpctl may be used to command a node to enter a new state, or to change permissions to use a node.

• bpctl -S <nodespec> -s <state>

State may be:

• reboot (node will reboot immediatly)
• halt (node halts)
• unavailable (only root may access the node)
• error (only root may access node)
• bpctl -v : print software version and exit.
• bpctl -h : show command help.
• bpctl <mode option>

where mode option is one of:

• -m <mode> <nodespec> where mode in octal (like a file mode)
• -g <group> <nodespec> where group is a user group
• -u <user> <nodespec> where user is a particular user that owns the node

Each slave node in the cluster is owned by a user and a group, and has an access mode. This is exactly like POSIX file permissions except that currently, only execute has meaning to the system. Thus, bpctl with -m, -u, or -g is like chmod, chown, and chgrp respectivly. These permissions come into play whenever a process attempts to migrate to another node in the cluster. This mechanism is primarily useful to enforce fair sharing or support reservations in a large cluster administrativly.