Wireless controllers in HA - upgrade steps

[M1LEN]

Hi guys, 

I am planning upgrade of a pair of wlcs in HA. 5508. Currently 8.2.166.0 version and upgrade to be to 8.3.150.0 (which is MD one recommended by Cisco). I found a link in the community  > https://community.cisco.com/t5/other-wireless-mobility-subjects/upgrade-wlc-s-firmware-with-high-availability-ap-sso-enabled/td-p/2451968 

but I have few questions on the procedure. 
So I plan to run the upgrade over Gui, http and to browse the file. I should do it on active peer IP, not on HA IP address, right?

after the file is downloaded to the computer it will automatically start transferring to the second controller (backup) , right?
Maybe once done I should be able to see with show boot , that the new image is downloaded to the second one. 

Then I think it is pretty straight forward to pre-download the new image to the APs. After this completes I will go to reboot both controllers by reset system both. 

Between I didn't consider the instructions very clear and also not mentioning upgrade of HA pair - https://www.cisco.com/c/en/us/td/docs/wireless/controller/release/notes/crn83mr5.html#t_upgrade-to-wlc-software_83mr5

Thanks in advance for any comment. 

Regards,

Milen

[marce1000]

 - The upgrade action  , should be started from the actve peer. It will also display an ongoing and active log screen for the whole upgrade process and the actions being taken on the standbye controller. It will also tell you when it is save to reboot the controller(s).

 M.

[RaffyLindogan]

Hi mate,

Yes, you should login to the active controller.
Download the image from there.
It will then transfer the image to the standby WLC.
Image will then be written to flash.
Then it will notify you after that the transfer has been completed.
Then that's at that time it will show on your boot, but would only take effect after reboot.
And yes, you can do the image pre-download of APs to minimize downtime.
Make sure that you configure the primary boot of APs "config boot primary"

Cheers,

Raffy