Management requests sent to a Host Controller immediately after the Host Controller had launched may have failed with an exception of type `NullPointerException`. This was because there was a period of time between when the Host Controller was able to receive requests and when the server management system had fully started. This period of time was usually less than one second, but any requests received in that time would fail.
This issue has been fixed in this release by making sure that a Host Controller will only receive requests once the server management system has fully started. As a result, there is no longer period of time where received requests will trigger a `NullPointerException` because the the server management system has not fully started.
There's a gap in the HostController boot sequence between when the external management interface services allow connections and when the ServerInventory service used internally by the HC for managing servers is available. If certain management requests that need to find info about servers come in during this window, an NPE occurs:
[Host Controller] 03:26:38,028 ERROR [org.jboss.as.controller.management-operation] (management-handler-thread - 4) JBAS014612: Operation ("read-attribute") failed - address: ([
[Host Controller] ("host" => "failover-h1"),
[Host Controller] ("server-config" => "failover-one")
[Host Controller] ]): java.lang.NullPointerException
[Host Controller] at org.jboss.as.host.controller.DomainModelControllerService$DelegatingServerInventory.determineServerStatus(DomainModelControllerService.java:788)
[Host Controller] at org.jboss.as.host.controller.operations.ServerStatusHandler.execute(ServerStatusHandler.java:66)
[Host Controller] at org.jboss.as.controller.operations.global.ReadAttributeHandler.doExecuteInternal(ReadAttributeHandler.java:177) [wildfly-controller-8.0.0.Beta2-SNAPSHOT.jar:8.0.0.Beta2-SNAPSHOT]
[Host Controller] at org.jboss.as.controller.operations.global.ReadAttributeHandler.doExecute(ReadAttributeHandler.java:97) [wildfly-controller-8.0.0.Beta2-SNAPSHOT.jar:8.0.0.Beta2-SNAPSHOT]
[Host Controller] at org.jboss.as.controller.operations.global.GlobalOperationHandlers$AbstractMultiTargetHandler.execute(GlobalOperationHandlers.java:151) [wildfly-controller-8.0.0.Beta2-SNAPSHOT.jar:8.0.0.Beta2-SNAPSHOT]
This shows up as fairly frequent failures in org.jboss.as.test.integration.domain.DomainControllerMigrationTestCase.testDCFailover. Any kind of automated tooling that started/reloaded/restarted an HC and then started polling for completion of server launch could hit the same issue.
Just noting that I've also seen this in my RBAC soak test: https://jenkins.mw.lab.eng.bos.redhat.com/hudson/job/eap-62-RBAC-QE-testsuite-soak/8/testReport/org.jboss.as.test.integration.domain.rbac/RbacSoakTest/soakTest/
Verified on EAP 6.3.0.DR1