A new task started in Plesk hangs after dist-upgrade from Debian 8

Symptoms

• A new task started in Plesk hangs (e.g. subscription creation, scan in WP Toolkit, update of extensions, etc.).

• The following error message appears in the Plesk Task Manager log /var/log/plesk/task-manager.log:

  ERROR task=324 process=324 trace=7247:60da61c35a000 Start failed: Failed to start the process: exit status 1 (/usr/bin/systemd-run: unrecognized option '--quiet')

• The server is running Debian OS which has been recently upgraded from Debian 8.

Cause

The systemd package has not been upgraded during the dist-upgrade from Debian 8. The installed package version is for Debian 8:

# apt-cache policy systemd | grep Installed
Installed: 215-17+deb8u13

Resolution

1. Connect to the Plesk server via SSH.

2. Update the systemd package:

   # apt-get install systemd -y

3. Remove the information about hung tasks from the Plesk database:

   # plesk db "DELETE longtasks, longtaskparams FROM longtasks LEFT JOIN longtaskparams ON longtasks.id = longtaskparams.task_id WHERE longtasks.status = 'not_started';"