Regression against DR15.
Authentication by legacy security realm is taken in account even if just Elytron authentication should be used. I don't say legacy authentication is used in priority before Elytron (that works as expected). Just that legacy authentication is somehow "initialized". In this case check "There are no user in mngmt-user.properties file" is performed

Reproducer:

• Configure Elytron authentication for management interface

  /subsystem=elytron/filesystem-realm=exampleFsRealm:add(path=fs-realm-users,relative-to=jboss.server.config.dir)
  /subsystem=elytron/filesystem-realm=exampleFsRealm/identity=user1:add()
  /subsystem=elytron/filesystem-realm=exampleFsRealm/identity=user1:set-password( clear={password="password123"})
  /subsystem=elytron/simple-role-decoder=from-roles-attribute:add(attribute=Roles)
  /subsystem=elytron/security-domain=exampleFsSD:add(realms=[{realm=exampleFsRealm,role-decoder=from-roles-attribute}],default-realm=exampleFsRealm,permission-mapper=default-permission-mapper)
  /subsystem=elytron/http-authentication-factory=example-fs-http-auth:add(http-server-mechanism-factory=global,security-domain=exampleFsSD,mechanism-configurations=[{mechanism-name=BASIC,mechanism-realm-configurations=[{realm-name=exampleApplicationDomain}]}])
  /core-service=management/management-interface=http-interface:write-attribute(name=http-authentication-factory, value=example-fs-http-auth)
  

• impossible to acces management interface

  curl --user user1:password123 http://localhost.localdomain:9990/management?operation=attribute\&name=server-state
  {
      "outcome" : "failed",
      "failure-description" : "WFLYDMHTTP0006: The security realm is not ready to process requests, see http://localhost.localdomain:9990/error",
      "rolled-back" : "true"
  }
  

Access is granted once

• security realm is undefined from management interface

  /core-service=management/management-interface=http-interface:undefine-attribute(name=security-realm)
  

• Or user is added into ManagementRealm

  ./add-user.sh -u admin -p admin -r ManagementRealm
  

curl --user user1:password123 http://localhost.localdomain:9990/management?operation=attribute\&name=server-state
"running"