Prerequisite tasks for configuring a cluster

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Before configuring the cluster, PowerHA® SystemMirror® must be installed on all the nodes, and connectivity must exist between the node where you are performing the configuration and all other nodes to be included in the cluster.

Network interfaces must be both physically and logically configured to the AIX® operating system so that communication occurs from one node to each of the other nodes. The PowerHA SystemMirror discovery process runs on all server nodes, not just the local node.

All node IP addresses and host names must be added to the /etc/cluster/rhosts file before configuring the cluster to verify that information is gathered from the systems that belong to the cluster.

After you have configured and powered on all disks and configured communication paths to other nodes in the AIX operating system, PowerHA SystemMirror automatically collects information about the physical and logical configuration. It displays this information in corresponding SMIT picklists.

PowerHA SystemMirror uses all configured interfaces on the cluster nodes for cluster communication and monitoring. All configured interfaces are used to keep cluster IP addresses highly available.

After you install PowerHA SystemMirror, verify that the following Cluster Aware AIX (CAA) entry is commented out in the /etc/inetd.conf file before creating PowerHA SystemMirror cluster.
caa_cfg stream tcp6 nowait root /usr/sbin/clusterconf 
clusterconf >>/var/adm/ras/clusterconf.log 2>&1
Starting with AIX 7.3, CAA entry in the /etc/inetd.conf file is already commented. During PowerHA SystemMirror installation, this CAA entry in the /etc/inetd.conf file is commented out for the following releases:
  • PowerHA SystemMirror Version 7.2.3 SP6, or later
  • PowerHA SystemMirror Version 7.2.4 SP4, or later
  • PowerHA SystemMirror Version 7.2.5 SP2, or later
  • PowerHA SystemMirror Version 7.2.6

If AIX 7.3 is installed with an earlier version of PowerHA SystemMirror than the versions listed previously, the CAA entry is not commented out automatically. You must manually comment out the CAA entry in the /etc/inetd.conf file.

To uncomment the CAA entry, run the following command on all the nodes of the cluster before creating the cluster: 
chsubserver -a -r inetd -v caa_cfg -p tcp6