https://community.cloudera.com/t5/Support-Questions/Null-Pointer-Exception-in-ambari-server-logs-after-ambari/m-p/230538#M192388 <P>Btw, for the records. Related to my comment below and your indications.</P><P>As guessed, no HUE entries are found in ambari db. E.g:</P><PRE>ambari=&gt; select * from hostcomponentstate where service_name = 'HUE'; id | cluster_id | component_name | version | current_stack_id | current_state | host_id | service_name | upgrade_state | security_state ----+------------+----------------+---------+------------------+---------------+---------+--------------+---------------+----------------(0 rows) </PRE><P>whereas, there are entries for Zeppeling, e.g.:</P><PRE>ambari=&gt; select * from hostcomponentstate where service_name = 'ZEPPELIN'; id | cluster_id | component_name | version | current_stack_id | current_state | host_id | service_name | upgrade_state | security_state -----+------------+-----------------+---------+------------------+---------------+---------+--------------+---------------+---------------- 101 | 2 | ZEPPELIN_MASTER | UNKNOWN | 1 | UNKNOWN | 2 | ZEPPELIN | NONE | UNKNOWN (1 row) </PRE> Wed, 17 May 2017 02:06:17 GMT rafael_gomez_g 2017-05-17T02:06:17Z