Removing Nodes From A Cluster - IBM Power Systems 775 Manual

After you create a stanza file, you pass the information to the following mkdef command:
cat lpar_stanza.txt | mkdef -z
Adding nodes into node groups in the cluster
After the nodes are defined, you add the nodes into the cluster groups to manage the nodes.
A node group is a named collection of cluster nodes that are used as a simple way to target
an action to a specific set of nodes. The node group names are used in any xCAT command
that targets a node range.
There are two ways to create xCAT static node groups: you set the groups attribute of the
node definition or you create a group definition directly, as shown in Example 5-50.
Example 5-50 Create a group definition by the mkdef command
# mkdef -t group -o aixnodes members="node01,node02,node03"
# lsdef -t group -o aixnodes
Object name: compute
grouptype=static
members=node01,node02,node03
You then manage the nodes by groups with xCAT commands.

5.3.3 Removing nodes from a cluster

This section describes the process of removing the nodes from the cluster.
Removing compute nodes
Complete the following steps to remove compute nodes from the service node and xCAT
database:
1. Check the status of the nodes:
a. Shut down the nodes if the status is "Running":
# rpower <noderange> stat
<noderange>: Running
# xdsh <noderange> -v shutdown -h now
b. Or, force that is powering off the nodes, but shut down gracefully:
# rpower <noderange> off
c. Recheck the status of the node:
# rpower <noderange> stat
2. Remove the node definitions of NIM machine from the service node:
# rmdsklsnode -V -f <noderange>
This action might cause a side affect of leaving the alloc_count of spot and share root for
the nodes to "1":
#/usr/sbin/lsnim -a alloc_count -Z GOLD_71Bdskls_1132A_HPC
#name:alloc_count:
GOLD_71Bdskls_1132A_HPC:1:
#/usr/sbin/lsnim -a alloc_count -Z GOLD_71Bdskls_1132A_HPC_shared_root
#name:alloc_count:
GOLD_71Bdskls_1132A_HPC_shared_root:1:
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