I have a pair of Cisco 5508 controllers with close to 50 APs shared between the two. After some maintainence - changing from (the unsupported) LACP to LAG for the port-channel I have repeated issues with WAPs rejoining controllers.
The first section shows the console output from an AP that performs the re-join. The second section shows the disparity between the AP up time and the Association up time.
*Jan 15 15:25:59.004: %DTLS-5-SEND_ALERT: Send FATAL : Close notify Alert to 10.0.0.102:5246
*Jan 15 15:25:59.096: %WIDS-6-DISABLED: IDS Signature is removed and disabled.
*Jan 15 15:26:10.000: %CAPWAP-5-DTLSREQSEND: DTLS connection request sent peer_ip: 10.0.0.102 peer_port: 5246
*Jan 15 15:26:12.135: %CAPWAP-5-DTLSREQSUCC: DTLS connection created sucessfully peer_ip: 10.0.0.102 peer_port: 5246
*Jan 15 15:26:12.139: %CAPWAP-5-SENDJOIN: sending Join Request to 10.0.0.102
*Jan 15 15:26:31.589: %DTLS-5-SEND_ALERT: Send FATAL : Close notify Alert to 10.0.0.102:5246
*Jan 15 15:26:42.000: %CAPWAP-5-DTLSREQSEND: DTLS connection request sent peer_ip: 10.0.0.102 peer_port: 5246
*Jan 15 15:26:44.268: %CAPWAP-5-DTLSREQSUCC: DTLS connection created sucessfully peer_ip: 10.0.0.102 peer_port: 5246
*Jan 15 15:26:44.268: %CAPWAP-5-SENDJOIN: sending Join Request to 10.0.0.102
*Jan 15 15:26:47.064: %CAPWAP-5-JOINEDCONTROLLER: AP has joined controller CONTROLLER2
*Jan 15 15:26:59.005: %WIDS-6-ENABLED: IDS Signature is loaded and enabled
OUTPUT FROM A "Show AP Uptime":
AP Name AP Up Time Association Up Time
------------ ----------------------- -----------------------
WAP01 375 days, 11 h 23 m 12 s 261 days, 01 h 19 m 52 s
WAP02 445 days, 09 h 21 m 28 s 222 days, 02 h 20 m 31 s
WAP03 215 days, 05 h 02 m 03 s 215 days, 05 h 00 m 26 s
[output cut]
TEST-AP 0 days, 01 h 21 m 51 s 0 days, 00 h 35 m 48 s
WAP04 136 days, 21 h 40 m 31 s 0 days, 00 h 14 m 50 s
WAP05 432 days, 10 h 20 m 00 s 0 days, 00 h 11 m 14 s
WAP06 332 days, 09 h 35 m 09 s 0 days, 00 h 03 m 38 s
Software version 8.2.130.0