Error 'Failed to connect to bus' during systemctl status check in RedHat 9

Products

• Network Observability
• Spectrum

Issue/Introduction

You encounter a bus connection error when attempting to check the status of a user-level systemd service․․․․․

ERROR MESSAGE:
"Failed to connect to bus: No medium found"

SYMPTOMS:

• Running sudo -u [User] systemctl --user status fails
• Bus connection cannot be established for user services

CONTEXT: This occurs when managing systemd user services via sudo on RedHat 9 environments․

 

Environment

OS: RedHat 9
any supported Spectrum release

Resolution

 

1. ENABLE USER LINGER: Enable the manager for the user to stay running after logout․

    loginctl enable-linger [User]

   EXPECTED: User linger is enabled, allowing user services to run persistently․

2. VERIFY USER SERVICE STATUS: Check the status of the user-level systemctl manager․

    sudo -u [User] systemctl --user status

   EXPECTED: Service status is displayed without bus connection errors․

 

Additional Information

you should no longer execute the processd or processd.pl binaries directly. Instead, processd has been moved to system units that rely on its initialization script.
The out-of-the-box systemd service file relies on the processd_init.sh script to handle the startup and shutdown procedures correctly.

See this:

Processd user errors after reboot

 

After updating your processd.service file, please run the following commands to clear the stuck activation and restart the service properly:

systemctl daemon-reload

systemctl stop processd

systemctl start processd

systemctl status processd (This should now show the service as active (running) instead of activating).