Clustered RH-SSO and LDAP outage

Issue

• Some, but not necessarily all LDAP servers become overloaded or hit 100% CPU
• The issue seems to only affect some of the servers in the cluster
• Some logins fail and some role credentials are missing

• RH-SSO has clustering errors in the log

  Caused by: org.infinispan.remoting.RemoteException: ISPN000217: Received exception from <server>, see cause for remote stack trace
      at org.infinispan.remoting.transport.jgroups.JGroupsTransport.checkRsp(JGroupsTransport.java:764)
      ...
      at org.jboss.as.clustering.jgroups.ClassLoaderThreadFactory.lambda$newThread$0(ClassLoaderThreadFactory.java:52)
      ... 1 more
  Caused by: java.io.StreamCorruptedException: ID_CLEAR_CLASS_CACHE token in the middle of stream processing
      at org.jboss.marshalling.river.RiverUnmarshaller.doReadObject(RiverUnmarshaller.java:738)
      ...
      at org.jgroups.blocks.RequestCorrelator.dispatch(RequestCorrelator.java:419)
      ... 26 more
  Caused by: an exception which occurred:
      in field loginUsername
      in object of type org.keycloak.models.sessions.infinispan.entities.UserSessionEntity
  

  Or an alternate version

  Caused by: java.lang.IllegalArgumentException: Can not set java.lang.String field org.keycloak.models.sessions.infinispan.entities.UserSessionEntity.loginUsername to java.lang.Class
      at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:167)
      ...
      at org.infinispan.remoting.transport.jgroups.CommandAwareRpcDispatcher.handle(CommandAwareRpcDispatcher.java:152)
      ... 28 more
  Caused by: an exception which occurred:
      in field loginUsername
      in object of type org.keycloak.models.sessions.infinispan.entities.UserSessionEntity
  

  And with SAML authentication

  ERROR [org.keycloak.saml.common] (default task-114) Error in base64 decoding saml message: org.keycloak.saml.common.exceptions.ProcessingException: PL00102: Processing Exception: