@FELIPE CABRAL Your /etc/hosts should look like this in the below example I used 192.168.0.124 as the IP of edcserver.domain please use the appropriate IP The first 2 lines shouldn't be tampered with # cat /etc/hosts 127.0.0.1 localhost localhost.localdomain ::1 localhost localhost.localdomain 192.168.0.124 edcserver.domain edcserver Now to overcome the error 1 other registered host (screenshot 2018-05-31-18-09-36-window.png) you have to delete this entry from 2 tables hoststate and hosts in the Ambari database. I have attached the procedure below, the assumption is as follows Ambari database name = ambari Ambari database type= MySQL Ambari database password =Secret1234 If you are using postgres please adapt accordingly the SQL Log on the DB # mysql -u root -pSecret1234 some output here Check the databases mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | ambari | | hive | | mysql | | oozie | | ranger | | rangerkms | | test | +--------------------+ 8 rows in set (0.00 sec) Connect to the Ambari database mysql> use ambari; Reading table information for completion of table and column names You can turn off this feature to get a quicker startup with -A Database changed Check the structure if hoststate table we need to delete the host_id mysql> describe hoststate; +-------------------+--------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------------------+--------------+------+-----+---------+-------+ | agent_version | varchar(255) | NO | | NULL | | | available_mem | bigint(20) | NO | | NULL | | | current_state | varchar(255) | NO | | NULL | | | health_status | varchar(255) | YES | | NULL | | | host_id | bigint(20) | NO | PRI | NULL | | | time_in_state | bigint(20) | NO | | NULL | | | maintenance_state | varchar(512) | YES | | NULL | | +-------------------+--------------+------+-----+---------+-------+ 7 rows in set (0.03 sec) mysql> select host_id from hoststate; +---------+ | host_id | +---------+ | 1 | +---------+ 1 row in set (0.04 sec) mysql> Delete from hoststate where host_id=1; Query OK, 1 rows affected (0.00 sec) Check the hosts table mysql> describe hosts; +------------------------+---------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +------------------------+---------------+------+-----+---------+-------+ | host_id | bigint(20) | NO | PRI | NULL | | | host_name | varchar(255) | NO | UNI | NULL | | | cpu_count | int(11) | NO | | NULL | | | cpu_info | varchar(255) | NO | | NULL | | | discovery_status | varchar(2000) | NO | | NULL | | | host_attributes | longtext | NO | | NULL | | | ipv4 | varchar(255) | YES | | NULL | | | ipv6 | varchar(255) | YES | | NULL | | | last_registration_time | bigint(20) | NO | | NULL | | | os_arch | varchar(255) | NO | | NULL | | | os_info | varchar(1000) | NO | | NULL | | | os_type | varchar(255) | NO | | NULL | | | ph_cpu_count | int(11) | YES | | NULL | | | public_host_name | varchar(255) | YES | | NULL | | | rack_info | varchar(255) | NO | | NULL | | | total_mem | bigint(20) | NO | | NULL | | +------------------------+---------------+------+-----+---------+-------+ 16 rows in set (0.02 sec) Retrieve and delete the host with the matching id 1 mysql> select host_id from hosts; +---------+ | host_id | +---------+ | 1 | +---------+ 1 row in set (0.00 sec) mysql> Delete from hoststate where host_id=1; Query OK, 1 rows affected (0.00 sec) And restart ambari-server and proceed with the registration all should be fine. Please revert If you found this answer addressed your question, please take a moment to log in and click the "accept" link on the answer. ... View more