Solved: Re: Migration of Cisco 9800 WLC 17.3.5a to 17.9.4a

AnilKumar95946 · ‎11-20-2023

We have currently 2 Cisco 9800 on prem CL-Controllers running version 17.3.5. Site A WLC is primary for endpoints in Site A and Site B is secondary WLC for endpoints in Site A and Vice versa. In our current setup we are running on low VM resources (HDD and memory). As per Cisco we can't extend the HDD as we need to rebuild the VMs again. We now built new VMs in 17.9.4a code. We now have migrate all our APs to these new controller. So my question is

1) What is the best strategy to cutover.? We don't want to change the Controllers IP.

2) How we can minimize the downtime? Site A is acting as secondary for Site B and Vice versa. Should we do the migration on both locations at same day or what should be our approach so that APs do not keep failing over on other WLC.

3) Please share any document or best practice approach in this regard.

Thanks

Haydn Andrews · ‎11-20-2023

Given each controller is secondary for the other site:

I would pre-download the 17.9.4a code to existing WLC and pre-download to the APs but not swap/ activate the image

Then build up new VMs

Have the config on them

Shut down Site As WLC

Turn on 17.9.4a WLC for Site A and change IP to be same as old WLC (ensuring it already has the config on it including tags if using static tags)

Fail Site A APs back to it, APs will reboot to change image and experience approx 5-15min outage

Would then fail Site B over and have same outage

Replace Site B WLC Fail back

Now point to note, could split the two but if primary WLC failed all APs would fail over and have to swap image and cause 5-15min outage - but that comes down to the risk appetite

*****Help out other by using the rating system and marking answered questions as "Answered"*****
*** Please rate helpful posts ***

View solution in original post