Restarting services fails with the message: "Failed to activate service 'org.freedesktop.systemd1': timed out"

Symptoms

Attempting to use the cPanel-provided scripts to restart services results in the script hanging up or timing out and failing to provide any meaningful output.

# [root@server ~]cPs# /scripts/restartsrv_mysql --status
Use of uninitialized value in string eq at /usr/local/cpanel/Cpanel/RestartSrv/Systemd.pm line 138.

Attempting to use Systemd to restart the services results in the action failing with a message similar to the following.

# [root@server ~]cPs# systemctl status tailwatchd
Failed to get properties: Failed to activate service 'org.freedesktop.systemd1': timed out

Additionally, messages similar to the following may be found in the system log.

CONFIG_TEXT: servicename.service: Failed with result 'timeout'.

Cause 

The problem experienced is a result of Systemd & the Dbus service encountering a deadlock in which these services can't interact with one another. This prevents Systemd from being able to interact with other services in the system. 

Resolution

The most known and reliable workaround for this is to restart your server. 

1. Log into WHM as the root user
2. Navigate to System Reboot / Graceful Reboot.
   Note: We do not recommend the user of the Forceful Reboot option unless the Graceful Reboot fails.
3. Once you are ready to reboot, click Proceed.

Additional Resources

Bug report with Dbus

Bug report with Systemd