Customizing Login screen in RHEL7

In Gnome Login screen there are several elements that can be customized. Once system admin had made this changes this will get apply to all the users in the organization. We can customized the greeter text, logo, keyboard layout and user list but we can't customize login screen background image.

1) Adding  Customized logo in Login screen :

i) Create the gdm profile with following contents in file /etc/dconf/profile/gdm :

user-db:user
system-db:gdm
file-db:/usr/share/gdm/greeter-dconf-defaults

 dconf is the name of gdm database.

ii) After that create a gdm database in /etc/dconf/db/gdm.d/01-logo with following contents:

[org/gnome/login-screen]
logo='/usr/share/pixmaps/poweredby.png`

Where /usr/share/pixmaps/ is the location where we store logo and poweredby.png is the name of the logo file.

iii) Once done above setting update the dconf database.

# dconf update

To verify logout from the session and try to login you will see at the bottom new customized logo which you have set.

2) Displaying a customized text banner in login screen :

 Follow above step (i) of creating gdm profile.

ii) After that create a gdm database in /etc/dconf/db/gdm.d/01-banner-message with following contents:

[org/gnome/login-screen]
banner-message-enable=true
banner-message-text='Welcome to Inside GNU LINUX'

iii) Once done above setting update the dconf database.

# dconf update

To verify logout from the session and try to login you will see at the top new customized banner text which you have set.

3)  Displaying multiple keyboard layout in login screen :

This will be  helpful for users who normally use different keyboard layout from the defaults and who wants to have that layout during login screen.

Codes of the desired language layouts are situated at /usr/share/X11/xkb/rules/base.lst file under the section layout.

From there you can view the different keyboard layouts available to choose from.

Use the localectl tool to change the system keyboard layout settings as follows:

# localectl set-x11-keymap in,us

Above command will set in as default layout and us as secondary layout.

4)  Customizing the default desktop background for all users :

   In organizations system administrator can set default background to all users and they can restrict users from changing there default background with following trick.

i) Create a local database for machine wide settings for setting background in /etc/dconf/db/local.d/00-backgroud:

# Specify the dconf path
[org/gnome/desktop/background]

# Specify the path to the desktop background image file
picture-uri='file:///usr/local/share/customizedbackground.jpg'
# Specify one of the rendering options for the background image:
# 'none', 'wallpaper', 'centered', 'scaled', 'stretched', 'zoom', 'spanned'
picture-options='scaled'
# Specify the left or top color when drawing gradients or the solid color
primary-color='000000'
# Specify the right or bottom color when drawing gradients
secondary-color='FFFFFF'

ii) To restrict users from changing background made changes in :

# vim /etc/dconf/db/local.d/locks/backgroud                                                                               # List the keys used to configure the desktop background
/org/gnome/desktop/background/picture-uri
/org/gnome/desktop/background/picture-options
/org/gnome/desktop/background/primary-color
/org/gnome/desktop/background/secondary-color

iii) Once done above setting update the dconf database.

# dconf update

To verify logout from the session and try to login you will see at the top new customized banner text which you have set.