Unable to access Plesk: /opt/psa/admin/bin/dnsmng: not found

Symptoms

• In an attempt to upgrade Plesk from 18.0.41 version to 18.0.42:

  ERROR: PleskUpgradeException: dnsmng failed: sh: 1: /opt/psa/admin/bin/dnsmng: not found (upgrade.php:46)
  0: /opt/psa/admin/plib/Upgrade/upgrade.php:46

• After Plesk is inaccessible with the same error or:

  Server Error
  500 PleskUtilException
  dnsmng failed: sh: /usr/local/psa/admin/bin/dnsmng: No such file or directory

• The bind9 component is either not installed on the server:

  # dpkg -l | grep bind9
  Empty Output

  Or the package plesk-dns-bind-driver is missing:

  # rpm -qa | grep bind
  bind-license-9.11.4-26.P2.el7_9.9.noarch
  bind-9.11.4-26.P2.el7_9.9.x86_64
  bind-utils-9.11.4-26.P2.el7_9.9.x86_64
  bind-export-libs-9.11.4-26.P2.el7_9.9.x86_64
  bind-libs-9.11.4-26.P2.el7_9.9.x86_64
  bind-chroot-9.11.4-26.P2.el7_9.9.x86_64
  bind-libs-lite-9.11.4-26.P2.el7_9.9.x86_64

• Custom dnsConnector can be found in ServiceNodeConfiguration database table:

  # plesk db "select * from ServiceNodeConfiguration where section = 'dnsConnector'"
  +---------------+--------------+---------------+-----------------------------------------------------------------+
  | serviceNodeId | section | name | value |
  +---------------+--------------+---------------+-----------------------------------------------------------------+
  | 1 | dnsConnector | custom | true |
  | 1 | dnsConnector | custom_script | "/opt/psa/bin/extension" --exec slave-dns-manager slave-dns.php |
  +---------------+--------------+---------------+-----------------------------------------------------------------+

Cause

Resolution

Workaround

If update is not possible for some reason you may try the following