12.3. Installing the Para-virtualized Drivers

1. Copy the RPMs for your hardware architecture to a suitable location in your guest operating system. Your home directory is sufficient. If you do not know which RPM you require verify against the table at Section 12.2, “Para-virtualization Restrictions and Support”.
2. Use the rpm command or the yum command to install the packages. The rpm utility will install the following four new kernel modules into /lib/modules/[%kversion][%kvariant]/extra/xenpv/%release:

   • the PCI infrastructure module, xen_platform_pci.ko,
   • the ballooning module, xen_balloon.ko,
   • the virtual block device module, xen_vbd.ko,
   • and the virtual network device module, xen_vnif.ko.
3. If the guest operating does not support automatically loading the para-virtualized drivers (for example, Red Hat Enterprise Linux 3) perform the required post-install steps to copy the drivers into the operating system specific locations.
4. Shut down your guest operating system.
5. Reconfigure the guest operating system's configuration file on the host to use the installed para-virtualized drivers.
6. Remove the “type=ioemu” entry for the network device.
7. Add any additional disk partitions, volumes or LUNs to the guest so that they can be accessed via the para-virtualized (xen-vbd) disk driver.
8. For each physical device, LUN, partition or volume you want to use the para-virtualized drivers you must edit the disk entry for that device in the libvirt configuration file.
9. A typical disk entry resembles the following:

   <disk type='file' device='disk'>
     <driver name='file'/>
     <source file='/dev/hda6'/>
     <target dev='hda'/>
   </disk>
   

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   Modify each disk entry, as desired, to use the para-virtualized by changing the driver elements as shown below.

   <disk type='file' device='disk'>
     <driver name='tap' type='aio'/>
     <source file='/dev/hda6'/>
     <target dev='xvda'/>
   </disk>
   

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10. Add any additional storage entities you want to use for the para-virtualized block device driver.
11. Restart your guest:

    # xm start YourGuestName

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    Where YourGuestName is the name of the configuration file or the guest operating system's name as defined in its configuration file in the name = "os_name" parameter.
12. Reconfigure the guest network.

1. Create directories to mount the block device image in.

   [root@rhel3]# mkdir /mnt/pvdisk_p1
   [root@rhel3]# mkdir /mnt/pvdisk_p2
   

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2. Mount the devices to the new folders.

   [root@rhel3]# mount /dev/xvdb1 /mnt/pvdisk_p1
   [root@rhel3]# mount /dev/xvdb2 /mnt/pvdisk_p2
   

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3. Verify the devices are mounted correctly.

   [root@rhel3]# df /mnt/pvdisk_p1
   Filesystem           1K-blocks      Used   Available Use%  Mounted on
   /dev/xvdb1               32000        15       31985   1%  /mnt/pvdisk_p1
   

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4. Update the /etc/fstab file inside the guest to mount the devices during the boot sequence. Add the following lines:

   /dev/xvdb1   /mnt/pvdisk_p1   ext3    defaults        1 2
   /dev/xvdb2   /mnt/pvdisk_p2   ext3    defaults        1 2
   

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1. Create directories to mount the block device image in.

   [root@rhel4]# mkdir /mnt/pvdisk_p1
   [root@rhel4]# mkdir /mnt/pvdisk_p2
   

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2. Mount the devices to the new folders.

   [root@rhel4]# mount /dev/xvdb1 /mnt/pvdisk_p1
   [root@rhel4]# mount /dev/xvdb2 /mnt/pvdisk_p2
   

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3. Verify the devices are mounted correctly.

   [root@rhel4]# df /mnt/pvdisk_p1
   Filesystem           1K-blocks      Used   Available Use%  Mounted on
   /dev/xvdb1               32000        15       31985   1%  /mnt/pvdisk_p1
   

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4. Update the /etc/fstab file inside the guest to mount the devices during the boot sequence. Add the following lines:

   /dev/xvdb1   /mnt/pvdisk_p1   ext3    defaults        1 2
   /dev/xvdb2   /mnt/pvdisk_p2   ext3    defaults        1 2
   

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Procedure 12.1. Enable para-virtualized drivers for a Red Hat Enterprise Linux Guest

1. Shutdown the virtual machine (use “#shutdown -h now” inside the guest).
2. Edit the guest configuration file in /etc/xen/<Your GuestsName> in the following ways:
   1. Remove the “type=ioemu” entry from the “vif=” entry.
   2. Add any additional disk partitions, volumes or LUNs to the guest so that they can be accessed via the para-virtualized (xen-vbd) disk driver.
   3. For each additional physical device, LUN, partition or volume add an entry similar to the one shown below to the “disk=” section in the guest configuration file. The original “disk=” entry might also look like the entry below.

      disk = [ "file:/var/lib/libvirt/images/rhel4_64_fv.dsk,hda,w"]
      

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   4. Once you have added additional physical devices, LUNs, partitions or volumes; the para-virtualized driver entry in your XML configuration file should resemble the entry shown below.

      disk = [ "file:/var/lib/libvirt/images/rhel3_64_fv.dsk,hda,w",
      "tap:aio:/var/lib/libvirt/images/UserStorage.dsk,xvda,w" ]
      

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      Note

      Use “tap:aio” for the para-virtualized device if a file-based image is used.
3. Boot the virtual machine using the virsh command:

   # virsh start YourGuestName

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1. Create directories to mount the block device image in.

   [root@rhel5]# mkdir /mnt/pvdisk_p1
   [root@rhel5]# mkdir /mnt/pvdisk_p2
   

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2. Mount the devices to the new folders.

   [root@rhel5]# mount /dev/xvdb1 /mnt/pvdisk_p1
   [root@rhel5]# mount /dev/xvdb2 /mnt/pvdisk_p2
   

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3. Verify the devices are mounted correctly.

   [root@rhel5]# df /mnt/pvdisk_p1
   Filesystem           1K-blocks      Used   Available Use%  Mounted on
   /dev/xvdb1               32000        15       31985   1%  /mnt/pvdisk_p1
   

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4. Update the /etc/fstab file inside the guest to mount the devices during the boot sequence. Add the following lines:

   /dev/xvdb1   /mnt/pvdisk_p1   ext3    defaults        1 2
   /dev/xvdb2   /mnt/pvdisk_p2   ext3    defaults        1 2
   

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1. Add the following lines to the /etc/modprobe.d/blacklist file. Blacklist 8139cp and 8139too for the RealTek 8139 and e1000 for the virtualized Intel e1000 NIC.

   8139cp
   8139too
   e1000

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2. Remove the old network scripts from the /etc/sysconfig/network-scripts directory.
3. Reboot the guest. The default network interface should now use the para-virtualized drivers.