Cisco Wireless Controllers: High Availability

A few gotcha's from bringing up a High Availability pair of Cisco 5508s.

1. Do not try to straight up follow Cisco's directions of upgrading from the boot up wizard
2. Bring up new interfaces in the same subnets as per directions etc. etc. 
3. First you have to upgrade both controllers to the same image (makes sense)
4. upgrade both controllers to the same FUS image
5. Manually set your HA Sku'd controller as secondary, even though cisco says it isn't necessary...
6. If you like the GUI, you won't be able to use it on the service port anymore, so delete your network route, and use it from the regular LAG interface management port.  If you are good with CLI then you can still use the service port
7. Enable SSO on your PRIMARY controller and let it reboot   (all of cisco's directions imply you should do this at the same time on both controllers, but that doesn't work)
8. Once the Primary controller is back up in SSO state, then you can enable SSO on the secondary controller, wait for it to reboot a couple times, and look for "ACTIVE HOT"
9. Tell your customers they now have sub-second failover and see them not care


Hopefully these can save someone a bit of troubleshooting