By default a full installation of CentOS 7 will have the GNOME graphical user interface (GUI) installed and it will load up after system boot, however if we have installed CentOS without a GUI installed we can always install one later, or optionally we can install a different GUI.
This quick guide will cover how to install the KDE Plasma desktop on CentOS 7, which will provide a GUI for working with the Linux system. While I don’t suggest using a GUI on a production server, it’s a good option if you’re using CentOS as a desktop.
The Plasma desktop is the default environment in many Linux distributions such as openSUSE and Kubuntu.
Install KDE Plasma In CentOS
While there are many different graphical user interfaces available for Linux, in this example we will be using KDE Plasma workspaces.
Installing the KDE Desktop is now as simple as installing the “KDE Plasma Workspaces” package group, which is already configured to install hundreds more packages that are required for a GUI installation.
[[email protected] ~]# yum groupinstall "KDE Plasma Workspaces" -y
Note that this may take a while, on my minimal installation I needed to download almost 1000 packages which took up almost 2GB of disk space.
Start The GUI
By default after installing these packages, the default target should have automatically updated, meaning that after a reboot the GUI will automatically be loaded. We can check the current default target as shown below.
[[email protected] ~]# systemctl get-default graphical.target
In this instance the target has been updated appropriately by installing these package groups. If it instead said multi-user.target, then you would need to update it manually.
The target is similar to the old run levels, in this case multi-user.target is equivalent to run level 3 meaning that after a reboot the GUI will not be loaded here. We can set the default to the graphical.target which is equivalent to run level 5.
[[email protected] ~]# systemctl set-default graphical.target Removed symlink /etc/systemd/system/default.target. Created symlink from /etc/systemd/system/default.target to /usr/lib/systemd/system/graphical.target. [[email protected] ~]# systemctl get-default graphical.target
While this has changed the default target which is accessed during system boot, our current target is still the multi-user.target. We can change to the GUI by performing ‘systemctl isolate graphical.target’ which will change us to the GUI immediately.
[[email protected] ~]# systemctl isolate graphical.target
Alternatively a system reboot would also work, as all future boots should boot to the graphical target by default.
When you’re at the login screen, simply select the cog icon and confirm that KDE Plasma Workspace is selected, as shown below. This preference should be remembered and automatically selected for next time. No other options are displayed here as we only have KDE installed, however if we also installed a package group such as “GNOME Desktop” we would have a selection to choose from.
Removing KDE Plasma
If you’ve installed the GUI on a server and realized that it was a terrible mistake, don’t worry! We can also undo this by simply using yum to remove the “KDE Plasma Workspaces” package group
[[email protected] ~]# yum groupremove "KDE Plasma Workspaces"
Carefully read through the packages that will be removed and ensure that this looks correct prior to removing packages or dependencies.
As shown we can easily install the KDE Plasma Workspaces desktop group of packages in CentOS 7 Linux, which will provide us with a graphical user interface that can be used for managing and interacting with the system.