sql connection failed

nova-*.log中一直出现 DBConnectionError: (OperationalError) (2013, 'Lost connection to MySQL server at \'re ading initial communication packet\'和sql connection failed，网上搜了下说把my.cnf中的bind-address=127.0.0.1注释掉，但是我的配置文件没有这句话，后来在my.cnf中加了句bind-address=0.0.0.0就好了-.-