Node Creation with Unknown MAC address(es)

A reset or powercycle of a node triggers a DHCP client request which embeds the node's MAC address. A head node with an interface that is listening on that private cluster network and which recognizes that MAC address will respond with an IP address that is associated with that MAC, unless directed to ignore that node. A ICE ClusterWare™ head node can be so directed to ignore the known-MAC node by using a _no_boot attribute (see _no_boot), and a ClusterWare 6 or 7 master node can employ a /etc/beowulf/config file masterorder configuration directive to consider this known-MAC node to be owned by another head/master node.

A ClusterWare DHCP server which does not recognize the incoming MAC will by default ignore the incoming DHCP client request. To override this default:

scyld-clusterctl --set-accept-nodes True

and then any head node that shares the same database will add that new MAC to the shared ClusterWare database, assign to it the next available node index and associated IP address, and proceed to attempt to boot the node.

If a ClusterWare 6 or 7 beoserv daemon is alive and listening on the same private cluster network, then that master node should have its /etc/beowulf/config specify nodeassign locked, which directs its beoserv to ignore unknown MAC addresses.

When all new nodes with previously unknown MAC addresses are thus merged into the ClusterWare cluster, then the cluster administrator should again reenable the default functionality with:

scyld-clusterctl --set-accept-nodes False

If multiple new nodes concurrently initiate their DHCP client requests, then the likely result is a jumbled assignment of indices and IP addresses. Cluster administrators often prefer nodes in a rack to have ordered indices and IP addresses. This ordered assignment can be accomplished by performing subsequent carefully crafted scyld-nodectl update actions, e.g.,

scyld-nodectl -i n10 update index=100
scyld-nodectl -i n11 update index=101
scyld-nodectl -i n12 update index=102
scyld-nodectl -i n10,n11,n12 reboot   # at a minimum, reboot the updated nodes

Note

Desired ordering can more easily be accomplished by performing the initial node resets or powercycling for each individual node in sequence, one at a time, and allowing each node to boot and get added to the database before initiating the next node's DHCP request.