Plesk inaccessible: ERROR: Zend_Db_Adapter_Exception: SQLSTATE[HY000] [2002] Connection refused

Symptoms

• Plesk login page shows the following error: 

  ERROR: Zend_Db_Adapter_Exception: SQLSTATE[HY000] [2002] Connection refused

• In /var/log/mysqld.log the following error can be found:

  [ERROR] /usr/sbin/mysqld: Can't create/write to file '/var/run/mysqld/mysqld.pid' (Errcode: 2 - No such file or directory)

• The following error may be found in /var/log/mariadb/mariadb.log file:

  [ERROR] mysqld: Can't create/write to file '/var/run/mariadb/mariadb.pid' (Errcode: 2)
  [ERROR] Can't start server: can't create PID file: No such file or directory
  mysqld_safe mysqld from pid file /var/run/mariadb/mariadb.pid ended

  ---

  CONFIG_TEXT:2020-08-05 1:04:22 0 [ERROR] mysqld: Can't create/write to file '/var/run/mariadb/mariadb.pid' (Errcode: 13 "Permission denied")
  2020-08-05 1:04:22 0 [ERROR] Can't start server: can't create PID file: Permission denied

• Directory /var/run/mysqld (for Debian and Ubuntu) or /var/run/mariadb/ (for CentOS) is absent or has incorrect permissions:

  Debian and Ubuntu:

  # ls -lad /var/run/mysqld
  ls: cannot access /var/run/mysqld: No such file or directory

  CentOS:

  # ls -lad /var/run/mariadb/
  ls: cannot access '/var/run/mariadb/': No such file or directory

Cause

MySQL directory is absent so the system cannot create PID file for the service on startup.

Resolution

Note: This article may require additional administrative knowledge to apply. If any help required, contact server’s administrator or hosting support.

1. Connect to the server via SSH.

2. Create the configuration file with necessary content:

   • For Debian/Ubuntu:

     # echo "d /var/run/mysqld 0755 mysql mysql -" >> /etc/tmpfiles.d/mysql.conf

   • For CentOS/RHEL/CloudLinux:

     # echo "d /var/run/mariadb 0755 mysql mysql -" >> /etc/tmpfiles.d/mysql.conf

3. Reboot the server.

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