登入openstack的在dashboard,提示說許可權驗證錯誤，有2種情況： 1. 密碼被人改了。 2. 系統發生了問題。
密碼確認沒人改，所以檢視/var/log/keystone-all.log日誌，發現一堆錯誤：
File "/usr/lib/python2.6/site-packages/keystone/assignment/core.py", line 262, in get_domain
return self.driver.get_domain(domain_id)
File "/usr/lib/python2.6/site-packages/keystone/assignment/backends/sql.py", line 526, in get_domain
return self._get_domain(session, domain_id).to_dict()
File "/usr/lib/python2.6/site-packages/keystone/assignment/backends/sql.py", line 519, in _get_domain
ref = session.query(Domain).get(domain_id)
File "/usr/lib64/python2.6/site-packages/sqlalchemy/orm/query.py", line 775, in get
return self._load_on_ident(key)
File "/usr/lib64/python2.6/site-packages/sqlalchemy/orm/query.py", line 2512, in _load_on_ident
return q.one()
File "/usr/lib64/python2.6/site-packages/sqlalchemy/orm/query.py", line 2184, in one
ret = list(self)
File "/usr/lib64/python2.6/site-packages/sqlalchemy/orm/query.py", line 2227, in __iter__
return self._execute_and_instances(context)
File "/usr/lib64/python2.6/site-packages/sqlalchemy/orm/query.py", line 2240, in _execute_and_instances
close_with_result=True)
File "/usr/lib64/python2.6/site-packages/sqlalchemy/orm/query.py", line 2231, in _connection_from_session
**kw)
File "/usr/lib64/python2.6/site-packages/sqlalchemy/orm/session.py", line 777, in connection
close_with_result=close_with_result)
File "/usr/lib64/python2.6/site-packages/sqlalchemy/orm/session.py", line 783, in _connection_for_bind
return engine.contextual_connect(**kwargs)
File "/usr/lib64/python2.6/site-packages/sqlalchemy/engine/base.py", line 2489, in contextual_connect
self.pool.connect(),
File "/usr/lib64/python2.6/site-packages/sqlalchemy/pool.py", line 236, in connect
return _ConnectionFairy(self).checkout()
File "/usr/lib64/python2.6/site-packages/sqlalchemy/pool.py", line 474, in checkout
self)
File "/usr/lib64/python2.6/site-packages/sqlalchemy/event.py", line 377, in __call__
fn(*args, **kw)
File "/usr/lib/python2.6/site-packages/keystone/common/sql/core.py", line 204, in mysql_on_checkout
dbapi_conn.cursor().execute('select 1')
File "/usr/lib64/python2.6/site-packages/MySQLdb/cursors.py", line 205, in execute
self.errorhandler(self, exc, value)
File "/usr/lib64/python2.6/site-packages/MySQLdb/connections.py", line 36, in defaulterrorhandler
raise errorclass, errorvalue
OperationalError: (1047, 'Unknown command')
這裡可以看出，是mysqldb引擎連線mysql進行資料操作mysql返回的錯誤，所以，基本判斷是mysql出問題了，登入mysql,查詢admin的密碼，發現連mysql的use命令都無法使用。所以引出了mysql的galera的問題。
mysql的galera是一種多主的mysql的HA方案，由單獨開發一段程式在mysql底層實現資料的複製，而在各個伺服器操作mysql上基本和單機沒有區別。 但是線上上沒有做任何修改，一直執行的過程中，發生了一個錯誤：
[root@node-10 conf.d]# mysql Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 30631 Server version: 5.5.28 Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql> use keystone; ERROR 1047 (08S01): Unknown command
我們應該知道mysql的use命令肯定是存在的。如果我們真實輸入一個不存在的命令，提示也應該是這樣的：
Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> test
-> ;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'test' at line 1
這裡先初步解決，讓伺服器執行起來，重啟服務即可
service mysql restart
注意，這裡/etc/init.d/mysql這個檔案是使用了galera的定製化的指令碼，理論上是將叢集中所有的mysql服務重啟，如果失敗，可以手動kill -9即可。
然後再登入openstack的HA環境，就可以成功了。