9800 ISSU upgrade problem

[schulcz]

Hi Guys,

I tried to upgrade a HA pair (SSO) from 17.3.5b to 17.6.3.

Process started, standby wlc downloaded image and new image predowload for APs was successful.

After that, the standy wlc starting to reboot, and after it comes back, log on active member shows this:

ERROR: MCL-Terminating the current ISSU Operation. ISSU Abort operation is initiated
ERROR: Once ISSU abort is done please check full list of mismatched commands via:
ERROR: show redundancy config-sync failures historic mcl
ERROR: install_activate  exit(2 ) Mon Sep 12 20:15:47 CET 2022

Standby reboot again and comes back with the original software, so it reverted back to the original state. I check "show redundancy config-sync failures historic mcl" on active, and shows username xxx priv 15 secret xxx rows from the config.

Wondering can I login to standby, tried it, I can't, it shows authentication failed. I added users on active again, after that I can login on standby also.

What cause the problem and what can I do? Is the ISSU forgettable?

[Leo Laohoo]

You're lucky it went well, @Rasika Nayanajith.

[Scott Fella]

I never truly like SSO:) I will tell you that ever since I have ran into issue with SSO and went with N+1, I never had any issue with upgrades enabling the hitless.  Maybe one day I will setup SSO in my lab and test this out more, I think I was lucky with upgrades only a few times.