1.mysql 啟動服務提示輸入密碼

1.解決mysql啟動服務過程中一直提示輸密碼，分析是mysql安裝時自動建立的linux user，運行passwd -d mysql后解決，在此記錄

root@ubuntu:/etc/init.d# service mysql start
 * A MySQL Server is already started
root@ubuntu:/etc/init.d# service mysql restart
 * Stopping MySQL Community Server 5.7.18
.....
 * MySQL Community Server 5.7.18 is stopped
 * Re-starting MySQL Community Server 5.7.18
[sudo] password for mysql:
Sorry, try again.
[sudo] password for mysql:
Sorry, try again.
[sudo] password for mysql:
Sorry, try again.
sudo: 3 incorrect password attempts
[sudo] password for mysql:
Sorry, try again.
[sudo] password for mysql:
Sorry, try again.
[sudo] password for mysql:
Sorry, try again.
sudo: 3 incorrect password attempts
..
 * MySQL Community Server 5.7.18 is started