systemd 常见问题

显示设备单元

~# systemctl --all --full -t device

运行时启用的服务

某些服务可能被禁用后也会在运行时启用：

~# systemctl is-enabled serial-getty@ttyAMA0.service
enabled-runtime

可以在 Generators 中查找依赖：

~# ls -l /run/systemd/generator/getty.target.wants/serial-getty@ttyAMA0.service
lrwxrwxrwx 1 root root 41 4月   2 01:37 /run/systemd/generator/getty.target.wants/serial-getty@ttyAMA0.service -> /lib/systemd/system/serial-getty@.service

如果需要强制禁用，可以：

~# systemctl mask serial-getty@ttyAMA0.service
Created symlink /etc/systemd/system/serial-getty@ttyAMA0.service → /dev/null.

此时的 is-enabled 状态：

~# systemctl is-enabled serial-getty@ttyAMA0.service
masked

也可以恢复：

~# systemctl unmask serial-getty@ttyAMA0.service
Removed /etc/systemd/system/serial-getty@ttyAMA0.service.