4.4. Installing the Linux guest agent

Although all the supported Linux distributions are natively paravirtualized (and thus do not need special drivers for full performance), XenServer includes a guest agent which provides additional information about the VM to the host. This additional information includes:

Linux distribution name and version (major, minor revision).
Kernel version (uname).
IP address of each Ethernet interface.
Total and free memory within the VM.

It is important to install this agent and keep it up-to-date (see Chapter 5, Updating VMs) as you upgrade your XenServer host.

To install the guest agent

The files required are present on the built-in xs-tools.iso CD image, or alternatively by using the “Install Tools” option in XenCenter.
Mount the image into the guest via:
```
mount /dev/xvdd /mnt
			
```
Execute the installation script as the root user:
```
/mnt/Linux/install.sh
			
```
If the VM was upgraded from XenServer 3.1, you will also need to run:
```
chkconfig xengmond off
			
```
If the kernel has been upgraded, or the VM was upgraded from a previous version, reboot the VM now.

Note

CD-ROM drives and ISOs attached to Linux Virtual Machines appear as /dev/xvdd instead of as /dev/cdrom as you might reasonably expect. This is because they are not "true" CD-ROM devices, but normal devices. When the CD is ejected by either XenCenter or the CLI, it hot-unplugs the device from the VM and the device disappears. This is different from Windows Virtual Machines, where the CD remains in the VM in an empty state.