Dev-mysql-maint error occurred during the installation of VHCS Control panel

Error message:

Can’t connect on ‘DBI:mysql:;localhost’ :Access denied for user ‘debian-sys-maint’@'localhost’ (using password: YES)

The issue occurring due to the absence of grant privilege (to the user dev-mysql-maint) on the databases.

You obtain details of "dev-mysql-maint" from /etc/mysql/debian.cnf.

One example is mentioned below:

# Automatically generated for Debian scripts. DO NOT TOUCH!
[client]
host = localhost
user = debian-sys-maint
password = 0nQp8g7pmupSbcpg
socket = /var/run/mysqld/mysqld.sock
[mysql_upgrade]
user = debian-sys-maint
password = 0nQp8g7pmupSbcpg
socket = /var/run/mysqld/mysqld.sock
basedir = /usr

You need to grant the privileges to dev-mysql-maint, according to the above information.

grant all privileges to *.* on 'dev-mysql-maint'@'localhost' identified by '0nQp8g7pmupSbcpg' with grant option;

Note: Modify the password according to the information in /etc/mysql/debian.cnf.

Grant lock and temp table privilege

To grant the Lock table privilege:
mysql
use mysql;
show tables;
update db set Lock_tables_priv='Y' where Db="DatabaseName" and User="DatabaseUsername";
flush privileges;

To grant the Temp table privilege:
mysql
use mysql;
show tables;
update db set Create_tmp_table_priv='Y' where Db='DatabaseName' and User="DatabaseUsername";
flush privileges;

Make sure that you had given flush privileges.

Modify the DatabaseUsername and DatabaseName according to the requirement.

Checking Mysql queries User had opened

You can run the following to obatin how many mysql queries a user has open:
mysqladmin pr | awk -F\| {'print $3'} | sort -nk1 | awk -F_ {'print $1'} |uniq -c |sort

Run the following to check the database with the most queries:
mysqladmin pr | awk -F\| {'print $5'} | sort -nk1 |uniq -c |sort