virtualbox.org

midpeter444 wrote:I already had the VBoxGuestAdditions.iso in the VB Settings as the default IDE drive. Still won't mount and doing sudo mount /dev/sr0 fails as before. I tried adding /dev/cdrom to /etc/fstab, but didn't help.

Well, the device name won't necessarily be /dev/sr0. If you do something like "grep 'CD-ROM' /var/log/kern.log" on your guest, what are the most recent lines?

Now I finally have VBoxLinuxAdditions.run file to run, but it fails to install the extensions to the X Window system due to "unknown version of X", which is another problem that means I still don't have a Linux guest working the way I want.

What happens if you do "X -version"? Note that's a single dash, not a double dash like most Linux-y programs.

What I really want is to have Centos running with Guest Additions. But I can't find the VBoxGuestAdditions.iso anywhere on the Centos file system to manually mount it as I did with the Xubuntu install. Can one just download the VBoxGuestAdditions.iso directly onto the guest and mount it and run it that way? Why does it have to be mounted from the host?

AFAIK it doesn't have to be mounted like that, but I could easily be wrong.

Since guest additions give you shared host/guest folders, you'd be doing network operations just to get the .iso from the host onto the guest in the first place, or downloading stuff from the net to the guest a second time.

@midpeter444,

/dev/sr0 is almost always the device name for the cd/dvd drive in modern Linux. cdrom or cdrom0 is almost always the mount point which can be a folder in the /media folder.
Note: the 0 in /dev/sr0 is a zero.

I sent a link that showed how to do all of this, but you seem to be having issues understanding the instruction.
First you should not have to manually mount the cd/dvd unless you already have a cd/dvd in the virtual drive. Usually all you need to do is to select to remove what ever is in the drive from the devices menu. If you are presented with a force remove/unmount, it would be better to actually eject it from the guest first. and then click the devices tab and install guest additions. This will mount the guest additions in the virtual cd/dvd drive and in most cases will auto start the installation. Some times it does not and you have to install them manually, by opening a terminal and usually in media there will be the GAs or another folder. Then you cd into that folder and see if the additions are there. Once you see the LinuxAdditions... You run them with the following.

Here is an example on my Oracle EL6 machine where the cd is mounted in /media
cd /media/VBOXADDITONS_4.2.10_84104 <enter> once you see this run the install command:
sudo ./VBoxLinuxAdditions.run

You also need to keep in mind that this will not install if you have not installed the packages necessary to build external kernel modules (also spelled out in the link I sent)
If you are really wanting CentOS you would install the same requirements as the Fedora example, but You may be having an issue with CentOS if it is the newest version. This happens when CentOS updates their build and VirtualBox has not included the necessary patches to allow for the newer kernel, or version of Xorg. Not much can be done about that since CentOS is not one of the official guests.

Personally I would stick with the *ubuntu version or use Debian until you have more experience with Linux. And if you are not using the latest version of VirtualBox (from VirtualBox.org) ( 4.2.10 ), I would definitely upgrade.

I finally have guest additions installed on Centos.

I downloaded the VBoxGuestAdditions_4.2.10.iso inside the Centos guest since mounting it within Xubuntu worked. (You can download it here from http://download.virtualbox.org/virtualbox/ -> navigate to your version)

But when I try on Centos:
sudo mount -t iso9660 ./VBoxGuestAdditions_4.2.10.iso /mnt/cdrom

I get the error message:
mount: /path/to/VBoxGuestAdditions_4.2.10.iso is not a block device.

So this works:
sudo mount -t iso9660 -o loop,ro ./VBoxGuestAdditions_4.2.10.iso /mnt/cdrom

Now I can cd to /mnt/cdrom and run sudo ./VBoxLinuxAdditions.run. After rebooting the guest, I now get full screen when I hit Host+F.