AIX OS Migration Issue

For managing NIM (Network Installation Manager) clients and servers on AIX, especially focused on troubleshooting an OS migration from AIX 7.2 to 7.3.

1. Checking communication between master and client
From master to client:
# rsh nimclient date

• This tests remote shell (rsh) communication from the NIM master to the client machine (nimclient ). If it doesn’t work:
• Check the .rhosts file on the client to ensure the master is allowed.
• Check if firewall ports are open for rsh communication.
• Alternatively, use nimsh which is NIM's preferred secure communication method.

From client to master:
# telnet nimclient 1058
This tests the connection from the client to the NIM master on port 1058 (default NIM port). If nimsh is used instead of rsh, port 3901 may need to be open for communication.

2. Managing the root volume group (rootvg) on the NIM client server
If the rootvg is mirrored, you may need to unmirror it before further operations:
# unmirrorvg rootvg hdiskX
This removes the mirror on hdisk5 from rootvg.
Then, reduce the volume group by removing the physical volume:
# reducevg -df rootvg hdiskX
-d removes all logical volumes on hdiskX
-f forces the removal
Then, mark the physical volume as clean so it can be reused or removed:
# chpv -c hdiskX
If you are dealing with altinst_rootvg (alternate installation rootvg):
# alt_rootvg_op -X altinst_rootvg
# chpv -c hdiskX
This removes the alternate rootvg.

3. Remove the NIM client machine from the NIM server
nim -o remove <MachineName>
This deletes the client machine's configuration from the NIM server.

4. Check /etc/hosts file on both NIM server and client
Ensure both machines know each other’s IP address and hostname for proper name resolution.

On NIM server:
# vi /etc/hosts
Add something like:
192.168.10.11 nimclient
On NIM client:
# vi /etc/hosts
Add:
192.168.10.11 nimserver

5. Define the NIM client machine on the NIM server
# smit nim_mkmac
This opens an interactive menu to create a NIM machine definition on the NIM server.

You enter parameters like:
NIM Machine Name (nimclient)
Machine Type (standalone)
Hardware Platform (chrp)
Kernel for Network Boot (64)
Communication Protocol (nimsh)
Network Interface details (ent-NetworkX)

This step registers the client in the NIM server’s database for further management.

6. Check the settings/attributes of the NIM client on the NIM master
# lsnim | grep nimclient
This lists the client’s configuration details stored on the NIM master.

7. Initialize the NIM client server (nimclient in your case)
Backup existing NIM info:
# cp -r /etc/niminfo /etc/niminfo.bkp
Run NIM client initialization:
# smitty niminit
This prompts for:
Machine name (nimclient)
Primary/Secondary network interface (enX)
Hostname of NIM master (nimserver)
communication protocol  (nimsh)

niminit sets up the client to be managed by the NIM master.

8. Verify the NIM config file on the client
# cat /etc/niminfo
This file contains the NIM client configuration (e.g., master hostname, communication protocol, interface used, etc.). Verify it matches the intended setup.

9. Run migration from AIX 7.2 to 7.3 from the NIM server
# nimadm -j <nimvgname> -c <nimclient> -s spot_7300-03-01 -l lpp_7300-03-01 -d hdiskX -Y

Explanation of options:
-j <nimvgname>: Name of the NIM volume group to be used.
-c <nimclient>: Client machine to be upgraded.
-s spot_7300-03-01: The spot resource, which is a boot image with the AIX 7.3 kernel for network booting.
-l lpp_7300-03-01: The lpp_source resource, which contains AIX 7.3 installation files.
-d hdiskX: Target disk on the client where AIX will be installed.
-Y: Runs the migration without interactive prompts (auto confirm).

This command performs the actual migration of the client OS from AIX 7.2 to 7.3 using NIM resources.