Issue/Introduction

This article provides initial diagnosis and handling guidance for a host disconnection caused by pressing Ctrl+Alt+Del in ZStack Cloud.

Environment

• Product: ZCF
• Component: Cloud
• Versions: 3.x-5.5.30

Symptoms

The host is disconnected, and the messages log shows that a virtual USB device was connected and Received SIGINT was received.

Possible causes

Someone pressed Ctrl+Alt+Del.

Resolution

• Modify the system configuration file to disable Ctrl+Alt+Del.

1. Sign in to the host console as root.
2. Run vi /etc/systemd/system/ctrl-alt-del.target to enter edit mode and modify the ctrl-alt-del.target file.
3. Add the following content to ctrl-alt-del.target:

    [Unit]
    Description=Disable Ctrl-Alt-Del

    [Service]
    ExecStart=/bin/true
    Type=oneshot

    [Install]
    WantedBy=multi-user.target

4. Save the changes and exit edit mode.
5. Run systemctl daemon-reload to reload the systemd configuration.
6. Run systemctl mask ctrl-alt-del.target to disable ctrl-alt-del.target.
7. Restart the system for the changes to take effect.

• Security training: Train operations personnel and prohibit casual use of Ctrl+Alt+Del to avoid host disconnections caused by accidental operations.
• Physical protection: Protect hosts by installing cabinet door locks, surveillance cameras, and other equipment to prevent unauthorized personnel from operating them.