I installed the GUI on Tencent Cloud server and failed to start LightDM:
[root @vm_0_11_centos GDM]# systemctl start lightdm
[root @vm_0_11_centos GDM]# systemctl status lightdm
● lightdm.service-light Display Manager
Loaded: loaded (/usr/lib/systemd/system/lightdm.service; enabled; Vendor presets: enabled)
Active: failed (Result: start-limit) since Sat 2020-04-04 12:02:18 CST; 6s ago
Docs: man:lightdm(1)
Process: 8495 ExecStart=/usr/sbin/lightdm (code=exited, status=1/FAILURE)
Main PID: 8495 (code=exited, status=1/FAILURE)
Apr 04 12:02:17 VM_0_11_centos systemd[1]: Unit lightdm.service entered failed state.
Apr 04 12:02:17 VM_0_11_centos systemd[1]: Triggering OnFailure= dependencies of lightdm.service.
Apr 04 12:02:17 VM_0_11_centos systemd[1]: lightdm.service failed.
Apr 04 12:02:18 VM_0_11_centos systemd[1]: lightdm.service holdoff time over, scheduling restart.
Apr 04 12:02:18 VM_0_11_centos systemd[1]: Stopped Light Display Manager.
Apr 04 12:02:18 VM_0_11_centos systemd[1]: start request repeated too quickly for lightdm.service
Apr 04 12:02:18 VM_0_11_centos systemd[1]: Failed to start Light Display Manager.
Apr 04 12:02:18 VM_0_11_centos systemd[1]: Unit lightdm.service entered failed state.
Apr 04 12:02:18 VM_0_11_centos systemd[1]: Triggering OnFailure= dependencies of lightdm.service.
Apr 04 12:02:18 VM_0_11_centos systemd[1]: lightdm.service failed.
Solution:
because the libdrm version is too low, so just update.
[root @vm_0_11_centos ~]# yum update libdrm
[root @vm_0_11_centos ~]# systemctl start lightdm
[root @vm_0_11_centos ~]# systemctl status lightdm
● lightdm.service-light Display Manager
the Loaded: the Loaded (/ usr/lib/systemd/system/lightdm. Service; enabled; Vendor presets: enabled)
Active: Active (running) since Sat 2020-04-04 22:21:33 CST; 6s ago
…
My cloud server instance type is a standard SA1, CENTOS 7.5-64-bit system.