AIX mksysb creation date

Something that I do quite frequently is verify that I have a valid mksysb image for the AIX LPAR that I’m about to make changes on (for example, before applying a service pack). You can do this from the AIX LPAR itself using the nimclient command.

kristijan@aix13 # nimclient -l -L -t mksysb aix13 | grep aix13
aix13_220720_img     mksysb
aix13_220713_img     mksysb
kristijan@aix13 # nimclient -l -l aix13_220720_img
aix13_220720_img:
   class         = resources
   type          = mksysb
   creation_date = Wed Jul 20 00:17:25 2022
   source_image  = aix13
   arch          = power
   Rstate        = ready for use
   prev_state    = unavailable for use
   location      = /mksysb/aix13/aix13_220720_img
   version       = 7
   release       = 2
   mod           = 5
   oslevel_r     = 7200-05
   oslevel_s     = 7200-05-04-2220
   alloc_count   = 0
   server        = master

In my AIX environment, I define a “valid” mksysb as one that was created within the last 2 weeks. Anything created after that date I’d be hesitant in restoring from. Parsing the creation_date with a shell script isn’t all that elegant. The python datetime module allows us to parse this easily.

The script does assume (on line 18) that your NIM mksysb resource names contain the hostname you’re running the script from.

#!/usr/bin/env python3
#
# Check that there is at least one mksysb for the client, and
# that the creation date of the mksysb is not older than 15 days

import sys
import socket
import subprocess
from datetime import datetime

# Get hostname
hostname = socket.gethostname()

# Get current time
current_time = datetime.now()

# Create list of mksysb resources from the NIM server
nim_mksysb_list = subprocess.check_output(f"/usr/sbin/nimclient -l -L -t mksysb {hostname} | /usr/bin/awk '/{hostname}/{{ print $1 }}'", shell=True, encoding='utf-8').split()
# If the subprocess above returns no values, the result is a
# single item list with an empty string. Let's strip that out.
nim_mksysb_list = filter(None, nim_mksysb_list)

# Parse list of NIM mksysb backups and compare creation date
if nim_mksysb_list:
    for mksysb in nim_mksysb_list:
        mksysb_creation_time = subprocess.check_output(f"/usr/sbin/nimclient -l -l {mksysb} | /usr/bin/awk -F = '/creation_date/{{ print $2 }}'", shell=True, encoding='utf-8').strip()
        mksysb_creation_time = datetime.strptime(''.join(mksysb_creation_time), '%c')
        elapsed = current_time - mksysb_creation_time
        if elapsed.days < 15:
            # mksysb found on NIM and is not older than 15 days
            sys.exit(0)
else:
    # List is empty, no mksysb backups on NIM.
    sys.exit(1)

# If we've made it this far, all mksysb's are older than 15 days
sys.exit(2)

The above script will return the following exit codes:

Exit code	Description
0	mksysb found and is not older than 15 days
1	no mksysb found
2	all mksysbs found are older than 15 days

The use of exit codes to determine the validity of a mksysb is because its intended use is part of a larger pipeline of checks that occur before an AIX LPAR is patched. It forms one of many pre-checks that are run on an AIX LPAR before it’s deemed healthy to be patched.