我是一个从apache学习hadoop和ambari的新手，我一直在尝试在我的ubuntu的virtualbox环境中安装ambari，但是遇到这个问题我已经筋疲力尽了。
1系统提示我“ambari服务器‘启动’成功完成”，如下所示

~# ambari-server start
Using python  /usr/bin/python2.7
Starting ambari-server
Ambari Server running with administrator privileges.
Organizing resource files at /var/lib/ambari-server/resources...
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...................
Ambari Server 'start' completed successfully.

但是，我无法通过http://127.0.0.1：8080“，当我检查服务器状态时，如下所示

~# ambari-server status
Using python  /usr/bin/python2.7
Ambari-server status
Ambari Server not running. Stale PID File at: /var/run/ambari-server/ambari-server.pid

当我检查/var/run/ambari-server/ambari-server.pid文件时

~# cat /var/run/ambari-server/ambari-server.pid 
2875

当我签入日志文件时，它以以下行开头

22 May 2015 10:59:42,876  INFO [main] Configuration:527 - Reading password from existing file
22 May 2015 10:59:43,073  INFO [main] Configuration:747 - Hosts Mapping File null
22 May 2015 10:59:43,074  INFO [main] HostsMap:60 - Using hostsmap file null
22 May 2015 10:59:45,169  INFO [main] ControllerModule:172 - Detected MYSQL as the database type from the JDBC URL
22 May 2015 10:59:45,253  INFO [main] ControllerModule:214 - Using c3p0 ComboPooledDataSource as the EclipsLink DataSource
22 May 2015 10:59:45,416  INFO [main] MLog:80 - MLog clients using log4j logging.
22 May 2015 10:59:46,124  INFO [main] C3P0Registry:204 - Initializing c3p0-0.9.1.1 [built 15-March-2007 01:32:31; debug? true; trace: 10]
22 May 2015 10:59:59,830 ERROR [main] DBAccessorImpl:99 - Error while creating database accessor 
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.

我在网上搜索，没有找到解决这个问题的办法。
顺便说一下，我还没有安装hadoop，不管这是不是问题所在？
提前谢谢。