Patching Without Reboots: Live Kernel Update

Minimizing downtime is Business-Vital for IBM AIX environments running mission-critical workloads. Live Kernel Update (LKU) enables administrators to apply kernel patches without rebooting, though traditional processes may still result in brief service interruptions. This feature has been a keystone for achieving near zero-downtime maintenance.

Business and Operational Benefits:

• Near-zero downtime: Applications continue running, though brief performance impact may occur during workload migration.
• Eliminates Maintenance Windows: Since no reboot is required, admins can patch systems during production hours rather than waiting for scheduled downtime.
• Safety Net: LKU creates a clone of the OS. If the update fails during the process, the original environment remains untouched and active.

LKU with Ansible

While LKU is powerful, it is a multi-step process involving storage validation, configuration files, and hardware orchestration. Ansible makes this enterprise-ready by:

• Improving Scalability: Performing LKU on a single LPAR is simple; performing it on 50 LPARs simultaneously requires the automation that Ansible provides.
• Improving Consistency: Ansible ensures the configuration is identical across all nodes and that pre-flight checks (like checking for free disk space) are never skipped.
• Improving Integration: It allows you to wrap the LKU process into a larger CI/CD pipeline or patching workflow, logging the output to a central location for auditing.

Step-by-Step: Executing LKU Using Unusable

• Prerequisites for Performing AIX Live Kernel Update:
  • AIX OS Version: Must be AIX 7.2 or higher.
  • Storage: An unused physical volume (hdisk) with sufficient capacity must be available for the alternate boot environment.
  • Management Connectivity: The LPAR must have a configured connection to Power VC to allow for the creation of the surrogate LPAR.
  • Fileset: The bos.live_update fileset must be installed on the target system.
  • Ansible Collection: The ibm.power_aix collection (version > 1.9.0) should be present on your Ansible control node to utilise the LKU module.
• I used the following playbook for performing LKU, you can make the changes as per your requirements:

1.  ---

2.  - name: Perform live kernel update operation on AIX

3.    hosts: "{{host_name}}"

4.    gather_facts: false

5.    vars:

6.      host_name: all

7.      pvc_name: <pvc_name>

8.      pvc_password: <password>

9.      pvc_user: root

10.     directory: /ifix_dir

11.

12.   tasks:

13.

14.     - name: To install all the updates and interim fixes that are available in the provided directory

15.       ibm.power_aix.lku:

16.         PVC_name: "{{ pvc_name }}"

17.         PVC_password: "{{ pvc_password }}"

18.         PVC_user: "{{ pvc_user }}"

19.         directory: "{{ directory }}"

20.         filesets_fixes: all

           Note: The ifix was copied to the /ifix_dir directory on the AIX target system before running the playbook. PVC_password can also be safely stored using Ansible vault, rather than hardcoded in the playbook.

• The LKU module uses geninstall -k internally for performing live kernel update. It handles all the steps required for live update operation to run successfully including the required checks, Power VC server authentication, etc.

• Run the following ansible command, providing the playbook containing tasks for performing live update: ansible-playbook -i <inventory> <location_to_playbook>

• When the ansible command is triggered, live update process will start. If you check the target system at this point of time, It will show “Live AIX update in progress”

• Ansible command will run for some time and if everything was correctly done, It will end up with success.
  Recap will look something like this: 

• If you visit the target system now, you’ll see “AIX live update completed”.

• You can also verify this by running emgr -l command on the target system, It should display the ifix that you wanted to install.

That’s how you can install a kernel iFix without a system reboot using AIX Live Kernel Update, automated through Ansible.

Conclusion

Performing a Live Kernel Update on AIX using Ansible represents the peak of modern administration. By combining the "non-disruptive" power of LKU with the "hands-off" efficiency of Ansible, organizations can maintain highly secure, up-to-date systems without sacrificing uptime. 

This approach effectively turns a high-risk maintenance event into a routine, automated task.

Hope you liked this blog. Happy automation!