Lost Root Password Recovery Using NIM

Lost root password recovery in AIX is relatively easy using nim.  There are some differences if the server in question has been imaged with a mksysb.  In this case, the ‘Access a root volume’ option may not successfully mount rootvg.  Here is how to get around that:

On the nim server, configure the nim client for a maintenance boot:

# nim -o maint_boot -a spot=install

 image> <host machinename>

Boot the client into SMS and, after configuring the network settings, etc., boot the system normally into the ‘Welcome To Base OS’ menu.

You will now see an option to ‘Start Maintenance Mode for System Recovery’ (option 3).  Choose this option and then ‘Access this volume and Start a Shell’.  Select 0 Continue. If the shell is given successfully use the ‘passwd’ command to change the root password.

# passwd
# sync;sync;sync;reboot

This is how lost password recovery is supposed to work.  However, if you get an error about getrootfs failing, use the following technique:

Identify the rootvg hdisk with lspv, import the disk and mount / .

# lspv
# importvg hdisk(x)
# mount /dev/hd4 /mnt

Next, we’ll create a temporary user with root’s ID.

# echo temproot::0:0::/:/usr/bin/ksh >> /mnt/etc/passwd
# sync
# cd /
# umount /mnt

Reboot and login as ‘temproot’.  Change root’s password.

# passwd root

Lastly, and most importantly, edit the /etc/passwd file and REMOVE temproot.

Have a better way to handle this?  Let us know in the comments.