To address the EM Console Service down, especially when EMCC is configured with multiple OMS and is running behind a load balancer:
#1 Check the service console definition, it should be in the form https://<slb hostname>:<slb port>/em/consoleStatus.jsp
#2 Change the service definition to bypass the load balancer, for example https://<oms1 hostname>:<oms port>/em/consoleStatus.jsp
If that works, then it may be an issue with the load balancer.
Revert the change.
#3 Check the load balancer logfile.
If the error below is reports, issue may be an handchake between the EMCC agents and the load balancer.
[net-EM] [ERROR:32] [OTD-10355] [] [pid: 17012] Error receiving request from 10.167.20.79 (SSL_ERROR_HANDSHAKE_FAILURE_ALERT: SSL peer was unable to negotiate an acceptable set of security parameters.)
#4 Check the agent logfile to confirm that issue
2020-05-26 16:37:36,330 [111:283568D5:GC.Executor.5 (oracle_beacon:EM Management Beacon:E2968DF875FCE0A34BFA0F64326013846A3A159D0BB320C50B7926E0671A1A98) (oracle_beacon:EM Management Beacon:E2968DF875FCE0A34BFA0F64326013846A3A159D0BB320C50B7926E0671A1A98:http_raw)] INFO - fetch: Error sending request. host = <slb hostname>, port = 443, uri = /em/consoleStatus.jsp javax.net.ssl.SSLHandshakeException: Unsupported curveId: 29 at sun.security.ssl.HandshakeMessage$ECDH_ServerKeyExchange.<init>(HandshakeMessage.java:1058) at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:300) at sun.security.ssl.Handshaker.processLoop(Handshaker.java:1037) at sun.security.ssl.Handshaker.process_record(Handshaker.java:965)
#5 Bounce the management agents, after having added the following two options in the file agent_inst/sysman/config/s_jvm_options.opt
-Dhttps.protocols=TLSv1,TLSv1.1,TLSv1.2 -Dcom.sun.net.ssl.enableECC=false