Question
=========
This is a basic Guide on how to change an active service address to a new IP address.

Cause
=====

Note: This assumes that new service IP is in a valid address range.
i.e for IPAT via aliasing it needs to be in a different subnet to the boot adapters.
For IPAT via replacement it needs to be in the same subnet as the boot adapters

Answer

1. Change the IP address in /etc/hosts of both nodes.

2. Change the service IP address in the smitty hacmp menus:
# smitty hacmp

Extended Configuration

Extended Resource Configuration

HACMP Extended Resources Configuration

Configure HACMP Service IP Labels/Addresses
Change/ Show a Service IP Label/Address
Select the svc IP label you wish to change from the list

In the New IP Label/Address field, enter the same IP label name e.g.
* IP Label/Address svc_ipat_via_aliasing
New IP Label/Address [svc_ipat_via_aliasing]

+
* Network Name [net_ether_01]
+
Alternate HW Address to accompany IP Label/Address []
3. Then run a sync/verify:
# smitty hacmp
Extended Configuration
Extended Verification and Synchronization

This can be done with cluster services active, the sync will run as a
dynamic event (DARE)

Note: As the service address has changed this will cause the resource
group to be brought offline/online
hacmp.out looks like this:
Nov 13 14:26:27 EVENT START: reconfig_resource_release
Nov 13 14:26:29 EVENT COMPLETED: reconfig_resource_release 0
Nov 13 14:26:34 EVENT START: reconfig_resource_release_fence
Nov 13 14:26:34 EVENT COMPLETED: reconfig_resource_release_fence 0
Nov 13 14:26:34 EVENT START: reconfig_topology_start
Nov 13 14:26:34 EVENT COMPLETED: reconfig_topology_start 0
Nov 13 14:26:34 EVENT START: reconfig_topology_complete
Nov 13 14:26:40 EVENT COMPLETED: reconfig_topology_complete 0
Nov 13 14:26:43 EVENT START: reconfig_resource_acquire_fence
Nov 13 14:26:48 EVENT COMPLETED: reconfig_resource_acquire_fence 0
Nov 13 14:26:48 EVENT START: reconfig_resource_acquire
Nov 13 14:26:48 EVENT COMPLETED: reconfig_resource_acquire 0
Nov 13 14:26:48 EVENT START: reconfig_resource_complete
Nov 13 14:26:50 EVENT COMPLETED: reconfig_resource_complete 0
Nov 13 14:27:21 EVENT START: swap_adapter bart net_ether_01 10.0.10.2
10.0.50.52
Nov 13 14:27:21 EVENT COMPLETED: swap_adapter bart net_ether_01
10.0.10.2 10.0.50.52 0