I have recently deployed 9800-40 WLC in HA. i was able to monitor active using RMI IP. But when i try to monitor standby using the same SNMP and RMI IP of standby, its not working. SNMP is getting timeout. Opened a ticket with monitoring tool vendor, he asked me to increase the timeout value which i did with no success. can you tell me how do i monitor standby?
Which WLC model are you taking about? AirOS wlc like 8540 for example, doesn´t allow monitor the standby WLC. I had this problem already. Actually, if you have Cisco Prime you may see some logs if samething happens with standby WLC but it will not like monitory the primary.
The reason is simple. The active WLC will answer on the VIP address, which means, any request sent to the cluster will be responded by active and not standby. Second, when SSO is enabled, there is no SNMP/GUI access on the service port for both the WLCs in the HA setup.