[root@ns510814 ~]# yum -y groupinstall "X Window System"
...
[root@ns510814 ~]# yum -y groupinstall "Desktop"
...
[root@ns510814 ~]# yum -y groupinstall "General Purpose Desktop"
...
[root@ns510814 ~]# startx
xauth:  creating new authority file /root/.serverauth.15535


X.Org X Server 1.15.0
Release Date: 2013-12-27
X Protocol Version 11, Revision 0
Build Operating System: c6b8 2.6.32-220.el6.x86_64 
Current Operating System: Linux ns510814.ip-192-99-9.net 3.14.32-xxxx-grs-ipv6-64 #1 SMP Tue Jun 30 18:50:21 CEST 2015 x86_64
Kernel command line: root=/dev/md2  ro
Build Date: 23 July 2015  05:32:11PM
Build ID: xorg-x11-server 1.15.0-36.el6.centos 
Current version of pixman: 0.32.4
	Before reporting problems, check http://wiki.centos.org/Documentation
	to make sure that you have the latest version.
Markers: (--) probed, (**) from config file, (==) default setting,
	(++) from command line, (!!) notice, (II) informational,
	(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(==) Log file: "/var/log/Xorg.0.log", Time: Sat Mar 26 13:22:58 2016
(==) Using config file: "/etc/X11/xorg.conf"
(==) Using system config directory "/usr/share/X11/xorg.conf.d"
Initializing built-in extension Generic Event Extension
Initializing built-in extension SHAPE
Initializing built-in extension MIT-SHM
Initializing built-in extension XInputExtension
Initializing built-in extension XTEST
Initializing built-in extension BIG-REQUESTS
Initializing built-in extension SYNC
Initializing built-in extension XKEYBOARD
Initializing built-in extension XC-MISC
Initializing built-in extension SECURITY
Initializing built-in extension XINERAMA
Initializing built-in extension XFIXES
Initializing built-in extension RENDER
Initializing built-in extension RANDR
Initializing built-in extension COMPOSITE
Initializing built-in extension DAMAGE
Initializing built-in extension MIT-SCREEN-SAVER
Initializing built-in extension DOUBLE-BUFFER
Initializing built-in extension RECORD
Initializing built-in extension DPMS
Initializing built-in extension Present
Initializing built-in extension X-Resource
Initializing built-in extension XVideo
Initializing built-in extension XVideo-MotionCompensation
Initializing built-in extension SELinux
Initializing built-in extension XFree86-VidModeExtension
Initializing built-in extension XFree86-DGA
Initializing built-in extension XFree86-DRI
Initializing built-in extension DRI2
Loading extension GLX
/root/Desktop was removed, reassigning DESKTOP to homedir
/root/Downloads was removed, reassigning DOWNLOAD to homedir
/root/Templates was removed, reassigning TEMPLATES to homedir
/root/Public was removed, reassigning PUBLICSHARE to homedir
/root/Documents was removed, reassigning DOCUMENTS to homedir
/root/Music was removed, reassigning MUSIC to homedir
/root/Pictures was removed, reassigning PICTURES to homedir
/root/Videos was removed, reassigning VIDEOS to homedir
gnome-session[15963]: devkit-power-gobject-WARNING: Couldn't connect to system bus: Failed to connect to socket /var/run/dbus/system_bus_socket: Conexión rehusada
gnome-session[15963]: WARNING: Could not connect to ConsoleKit: Failed to connect to socket /var/run/dbus/system_bus_socket: Conexión rehusada
gnome-session[15963]: WARNING: Could not connect to ConsoleKit: Failed to connect to socket /var/run/dbus/system_bus_socket: Conexión rehusada
GNOME_KEYRING_SOCKET=/home/root/tmp/keyring-9GSVBx/socket
SSH_AUTH_SOCK=/home/root/tmp/keyring-9GSVBx/socket.ssh
GNOME_KEYRING_PID=15993

** (gnome-settings-daemon:15992): WARNING **: Connection failed, reconnecting...

** (gnome-panel:16023): CRITICAL **: panel_key_file_load_from_uri: assertion `uri != NULL' failed

** (gnome-panel:16023): CRITICAL **: panel_key_file_load_from_uri: assertion `uri != NULL' failed

** (gnome-panel:16023): CRITICAL **: panel_applet_frame_change_background: assertion `PANEL_IS_WIDGET (GTK_WIDGET (frame)->parent)' failed

** (gnome-panel:16023): WARNING **: panel-applet-frame.c:1359: failed to load applet OAFIID:GNOME_FastUserSwitchApplet (cannot get property bag):
Unknown CORBA exception id: 'IDL:omg.org/CORBA/INV_OBJREF:1.0'

(gnome-panel:16023): Gtk-WARNING **: A floating object was finalized. This means that someone
called g_object_unref() on an object that had only a floating
reference; the initial floating reference is not owned by anyone
and must be removed with g_object_ref_sink().
gnome-session[15963]: WARNING: Could not connect to ConsoleKit: Failed to connect to socket /var/run/dbus/system_bus_socket: Conexión rehusada
gnome-session[15963]: WARNING: Could not connect to ConsoleKit: Failed to connect to socket /var/run/dbus/system_bus_socket: Conexión rehusada
gnome-session[15963]: WARNING: Could not connect to ConsoleKit: Failed to connect to socket /var/run/dbus/system_bus_socket: Conexión rehusada
gnome-session[15963]: WARNING: Could not connect to ConsoleKit: Failed to connect to socket /var/run/dbus/system_bus_socket: Conexión rehusada

** (gnome-settings-daemon:15992): WARNING **: Connection failed, reconnecting...

** (gnome-settings-daemon:15992): WARNING **: Connection failed, reconnecting...

** (gnome-settings-daemon:15992): WARNING **: Connection failed, reconnecting...

** (gnome-settings-daemon:15992): WARNING **: Connection failed, reconnecting...

** (gnome-settings-daemon:15992): WARNING **: Connection failed, reconnecting...

** (gnome-settings-daemon:15992): WARNING **: Connection failed, reconnecting...

** (gnome-settings-daemon:15992): WARNING **: Connection failed, reconnecting...
^C
waiting for X server to shut down gnome-session: Fatal IO error 11 (Recurso no disponible temporalmente) on X server :0.
gnome-settings-daemon: Fatal IO error 11 (Recurso no disponible temporalmente) on X server :0.
error setting MTRR (base = 0xf9000000, size = 0x01000000, type = 1) Invalid argument (22)
(EE) Server terminated successfully (0). Closing log file.


xinit:  unexpected signal 2.
[root@ns510814 ~]# chkconfig --list messagebus
messagebus     	0:desactivado	1:desactivado	2:activo	3:activo	4:activo	5:activo	6:desactivado
[root@ns510814 ~]# /etc/init.d/dbus status && /etc/init.d/consolekit status 
-bash: /etc/init.d/dbus: No existe el fichero o el directorio
[root@ns510814 ~]# service dbus status
dbus: service desconocido
[root@ns510814 ~]# 

[root@ns510814 ~]# yum install dbus
Complementos cargados:fastestmirror, refresh-packagekit
Configurando el proceso de instalación
Loading mirror speeds from cached hostfile
 * base: centos.bhs.mirrors.ovh.net
 * epel: mirrors.mit.edu
 * extras: centos.bhs.mirrors.ovh.net
 * rpmforge: repoforge.mirror.constant.com
 * updates: centos.bhs.mirrors.ovh.net
El paquete 1:dbus-1.2.24-8.el6_6.x86_64 ya se encuentra instalado con su versión más reciente
Nada para hacer