it is pretty cool… a 32Bit Linux Host can run a 64Bit Linux guest. NICE 😉

i assume you have a working CentOS7 basic installation and are root.

tested on/with:

tested with: Host: Debian 8 Jessie

Operating System: Debian GNU/Linux 8 (jessie)
Kernel: Linux 3.16.0-4-686-pae
Architecture: x86

running VirtualBox 5.2.2

Guest: CentOS7

hostnamectl
   Static hostname: localhost.localdomain
    Virtualization: kvm
  Operating System: CentOS Linux 7 (Core)
       CPE OS Name: cpe:/o:centos:centos:7
            Kernel: Linux 3.10.0-693.11.1.el7.x86_64
      Architecture: x86-64

now let’s go:

yum update && yum upgrade; # first you will have to get CentOS7 up to date
yum install htop; # i just love this tool
yum install epel-release; # whatever this does
yum groupinstall "X Window system"; # this installs the basic grafical system
yum groupinstall "MATE Desktop"; # this installs mate
systemctl isolate graphical.target; # this makes linux boot the grafical profile per default
unlink /etc/systemd/system/default.target
ln -s /usr/lib/systemd/system/graphical.target /etc/systemd/system/default.target

reboot; # you might reboot now or not

now i hope you have mate up and running and want to install those cool integration tools: let’s install the virtualbox additions:

you will have to insert the virtual cd into the virtual cdrom drive like this:

this should do the job:

mkdir /virtualbox; # i copy the files from cdrom to harddisk /virtualbox... just got used to this workflow.
mount; # checkout where cdrom was mounted

cd /run/media/user/VBox_GAs_5.2.2/; # in my case cdrom.iso was mounted here

cp -rv * /virtualbox/
cd /virtualbox/

yum install kernel-devel; # what you will need to compile the guest additions module
yum install gcc make perl
./VBoxLinuxAdditions.run

reboot; # reboot system to load kernel modules

proof that it is working

admin