查看error日志：

cat /var/log/httpd/error.log

[Thu Oct 13 13:37:00 2016] [error] raise exceptions.ConnectionFailed(reason=_("Maximum attempts reached"))

[Thu Oct 13 13:37:00 2016] [error] ConnectionFailed: Connection to neutron failed: Maximum attempts reached

neutron日志显示neutron的用户密码：

cat /var/log/neutron/server.log

perationalError: (OperationalError) (1045, "Access denied for user 'neutron'@'controller' (using password: YES)") None None

进入mysql查看果然：

[root@controller p_w_picpaths]# mysql -uroot -p123456

mysql> SELECT user,host,password FROM mysql.user;

+----------+------------+-------------------------------------------+

| user     | host       | password                                  |

+----------+------------+-------------------------------------------+

| root     | localhost  | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| root     | controller | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| root     | 127.0.0.1  | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| keystone | localhost  | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| keystone | %          | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| glance   | localhost  | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| glance   | %          | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| nova     | localhost  | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| nova     | %          | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| neutron  | localhost  |                               |

| neutron  | %          |                               |

| cinder   | localhost  | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| cinder   | %          | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| heat     | localhost  | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| heat     | %          | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| sahara   | localhost  | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| sahara   | %          | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

+----------+------------+-------------------------------------------+

17 rows in set (0.06 sec)

解决：（重新建立用户，并授权）

mysql> drop database neutron;

mysql> create database neutron;

mysql> GRANT ALL PRIVILEGES ON neutron.* TO 'neutron'@'localhost' IDENTIFIED BY '123456';

mysql> GRANT ALL PRIVILEGES ON neutron.* TO 'neutron'@'%' IDENTIFIED BY '123456';

mysql> SELECT user,host,password FROM mysql.user;

+----------+------------+-------------------------------------------+

| user     | host       | password                                  |

+----------+------------+-------------------------------------------+

| root     | localhost  | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| root     | controller | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| root     | 127.0.0.1  | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| keystone | localhost  | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| keystone | %          | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| glance   | localhost  | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| glance   | %          | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| nova     | localhost  | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| nova     | %          | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| neutron  | localhost  | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| neutron  | %          | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| cinder   | localhost  | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| cinder   | %          | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| heat     | localhost  | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| heat     | %          | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| sahara   | localhost  | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

| sahara   | %          | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |

+----------+------------+-------------------------------------------+

重启mysqld 、memcached 、httpd、neutron-server 服务

成功解决，登录正常进入dashboard界面。