Unable to start MySQL: Access denied for user ‘debian-sys-maint’@’localhost’ (using password: YES)

Symptoms

While trying to start MySQL service, the following error can be found in /var/log/mariadb/mariadb.log or /var/log/mysql/error.log error log:

Version check failed. Got the following error when calling the 'mysql' command line client
ERROR 1045 (28000): Access denied for user 'debian-sys-maint'@'localhost' (using password: YES)
FATAL ERROR: Upgrade failed

Cause

MySQL upgrade was started and not completed successfully. Defined password in MySQL database is incorrect.

Resolution

1. Login to the server via SSH.

2. Find password for debian-sys-maint user in /etc/mysql/debian.cnf :

   # grep ‘password’ /etc/mysql/debian.cnf
   password = PASSWORD
   password = PASSWORD

3. Stop MySQL:

   # service mysql stop

4. Add
skip-grant-tables
option into
/etc/mysql/my.cnf
in
[mysqld]
section.

5. Start MySQL:

   # service mysql start

6. Login in MySQL:

   # plesk db

   MYSQL_LIN: > use mysql

7. Update the password which is defined in /etc/mysql/debian.cnf :

   MYSQL_LIN: > UPDATE mysql.user SET Password = password(‘PASSWORD’) WHERE User = ‘debian-sys-maint’;

8. Remove skip-grant-tables option in /etc/mysql/my.cnf :

9. Restart mysql

   # service mysql start