[CentOS] CentOS-7 Screen black after boot

Thu Jul 7 05:01:31 UTC 2016
Venkata Balaji N <nag1010 at gmail.com>

On Thu, Jul 7, 2016 at 2:00 PM, Hersh <parikhh1 at gmail.com> wrote:

> Hi Venkata,
> Can you please let me know the steps which you have followed for
> re-installing the GNOME? I am having a similar problem on one of our
> system.

To my understanding, when you install centos-7 with options ServerGUI or
GNOME Desktop and leave the system for long time locked, you will notice
that CentOS slips into textual interface mode and you will not be able to
get GUI which means, you can login to the system and cannot see GUI screen.

I have found the following steps on google, which helped me get through
this problem

systemctl disable gdm.service
systemctl enable lightdm.service
systemctl set-default graphical.target

First command was successful, second one error'd out. Not sure what to do,
i reverted back the first command and executed the third command and
rebooted. All worked fine !

Below is the log -

[root at buildhost ~]# systemctl disable gdm.service
Removed symlink /etc/systemd/system/display-manager.service.

[root at buildhost ~]# systemctl enable lightdm.service
Failed to execute operation: Access denied

[root at buildhost ~]# systemctl disable gdm.service

[root at buildhost ~]# systemctl enable gdm.service
Created symlink from /etc/systemd/system/display-manager.service to

[root at buildhost ~]# systemctl set-default graphical.target
Removed symlink /etc/systemd/system/default.target.

I think, the last command made sense to me.