执行ambari-server setup……的命令时并没有让配置数据库什么的信息，这种情况等你后面启动服务时就会报错了，
此时再执行一次setup操作就看到配置数据库了，
正常setup应该是这样的，
[root@hadoop1 hadoop]# ambari-server setup
Using python /usr/bin/python
Setup ambari-server
Checking SELinux...
SELinux status is 'enabled'
SELinux mode is 'permissive'
WARNING: SELinux is set to 'permissive' mode and temporarily disabled.
OK to continue [y/n] (y)? y
Customize user account for ambari-server daemon [y/n] (n)? n
Adjusting ambari-server permissions and ownership...
Checking firewall status...
Checking JDK...
[1] Oracle JDK 1.8 + Java Cryptography Extension (JCE) Policy Files 8
[2] Custom JDK
==============================================================================
Enter choice (1): 2
WARNING: JDK must be installed on all hosts and JAVA_HOME must be valid on all hosts.
WARNING: JCE Policy files are required for configuring Kerberos security. If you plan to use Kerberos,please make sure JCE Unlimited Strength Jurisdiction Policy Files are valid on all hosts.
Path to JAVA_HOME: /usr/java/jdk1.8.0_151
Validating JDK on Ambari Server...done.
Check JDK version for Ambari Server...
JDK version found: 8
Minimum JDK version is 8 for Ambari. Skipping to setup different JDK for Ambari Server.
Checking GPL software agreement...
GPL License for LZO: https://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html
Enable Ambari Server to download and install GPL Licensed LZO packages [y/n] (n)? n
Completing setup...
Configuring database...
Enter advanced database configuration [y/n] (n)? y
Configuring database...
==============================================================================
Choose one of the following options:
[1] - PostgreSQL (Embedded)
[2] - Oracle
[3] - MySQL / MariaDB
[4] - PostgreSQL
[5] - Microsoft SQL Server (Tech Preview)
[6] - SQL Anywhere
[7] - BDB
==============================================================================
Enter choice (1): 3
Hostname (localhost): localhost
Port (3306): 3306
Database name (ambari): ambari
Username (ambari): ambari
Enter Database Password (bigdata):
Configuring ambari database...
Configuring remote database connection properties...
WARNING: Before starting Ambari Server, you must run the following DDL against the database to create the schema: /var/lib/ambari-server/resources/Ambari-DDL-MySQL-CREATE.sql
Proceed with configuring remote database connection properties [y/n] (y)? y
Extracting system views...
ambari-admin-2.7.1.0.169.jar
....
Ambari repo file doesn't contain latest json url, skipping repoinfos modification
Adjusting ambari-server permissions and ownership...
Ambari Server 'setup' completed successfully.
如果不是上面那样输出，会报以下错误：
启动服务时的报错信息：
ambari-server start
Using python /usr/bin/python
Starting ambari-server
ERROR: Exiting with exit code -1.
REASON: DB Name property not set in config file.
- If this is a new setup, then run the "ambari-server setup" command to create the user
- If this is an upgrade of an existing setup, run the "ambari-server upgrade" command.
Refer to the Ambari documentation for more information on setup and upgrade.
一般情况是数据库配置有问题，我这里是数据库登录密码错了，跟着教程配置的，结果配置启动链接数据库的信息时用了默认的登录密码，直接去数据库里改对密码就好了，
启动正确的命令行输出信息是这样的：
[root@hadoop1 hadoop]# ambari-server start
Using python /usr/bin/python
Starting ambari-server
Ambari Server running with administrator privileges.
Organizing resource files at /var/lib/ambari-server/resources...
Ambari database consistency check started...
Server PID at: /var/run/ambari-server/ambari-server.pid
Server out at: /var/log/ambari-server/ambari-server.out
Server log at: /var/log/ambari-server/ambari-server.log
Waiting for server start......................................
Server started listening on 8080
DB configs consistency check: no errors and warnings were found.
Ambari Server 'start' completed successfully.