switching problem HA C9800-L

[Electronic20]

hello community,

I have 2 WLC C9800-L in HA, where chassis 1 is active and chassis 2 is on standby, I show image:

The WLC chassis 1 was disconnected and chassis 2 enters active mode, I show the image:

But when we connect the WLC chassis 1 it does not return to its active state, it stays in standby mode, I show the image:

Why doesn't it automatically switch chassis 1 as active since it was initially working like this?

[Flavio Miranda]

Hello @Electronic20 

 This is the expected behavior.  There is not preempt in WLC HA, which means, in case the switchover happens, it will stay as is unless you force the switchover back.

 The reason for that is probably to avoid issue as the switchover  does not happen by chance.  That´s way you, as admin, need to act and fall back the switchover considering you checked the environment and are sure nothing is wrong.

[Electronic20]

Thank you, in this case for chassis 1 to take the active function I forced it with this command:

redundancy force-switchover.

In any case, could you share or where could I get the cisco documentation where it indicates that way of working?

Regards

[Flavio Miranda · Accepted solution]

It should be in a guide like this below.  But it is not. What you can see there is they talking about Priority. You can define priority to chassis and IF they both boot, the chassis with higher priority will become the active chassis.

 But, this is in case both chassis boots. If a problem happen in one chassis and the second takes over, then it will not  switchover back.

 Meaning, I  have no document from Cisco at this time to show you but I´ve been seing this behavior since older WLCs.

https://www.cisco.com/c/en/us/td/docs/wireless/controller/9800/config-guide/b_wl_16_10_cg/high-availability.html

[Daniel Ordóñez Flores · Accepted solution]

Hi @Electronic20 

WLC 9800 SSO don`t use preemption, so if you want to get back WLC 1 as active, you need to do a 2redundancy force-switchover."