Installing Native KVM Drivers

Scenarios

When optimizing a Linux private image, you need to install native KVM drivers on the ECS. If the drivers have been installed, skip this section.

If you do not install KVM drivers, NICs of the ECS may not be detected and the ECS cannot communicate with other resources.

Prerequisites

• The ECS needs to be optimized. For details, see Checking Whether a Private Image Needs to be Optimized.
• The ECS kernel must be later than 2.6.24.
• Disable your antivirus and intrusion detection software. You can enable the software after KVM drivers are installed.

Procedure

Modify the configuration file based on the OS version.

CentOS and EulerOS

1. Run the following command to open the /etc/dracut.conf file:

   vi /etc/dracut.conf

2. Press i to enter the editing mode and add VirtIO drivers to add_drivers (the format varies depending on the OS).

   [root@CTU10000xxxxx ~]# vi /etc/dracut.conf 
   # additional kernel modules to the default 
   add_drivers+="virtio_blk virtio_scsi virtio_net virtio_pci virtio_ring virtio" 
   ....

3. Press Esc, enter :wq, and press Enter. The system saves the change and exits the /etc/dracut.conf file.
4. Run the following command to regenerate initrd:

   dracut -f /boot/initramfs-2.6.32-573.8.1.el6.x86_64.img

   If the virtual file system is not the default initramfs, run the dracut -f Name of the initramfs or initrd file actually used command. The actual initramfs or initrd file name can be obtained from the grub.cfg file, which can be /boot/grub/grub.cfg, /boot/grub2/grub.cfg, or /boot/grub/grub.conf depending on the OS.

5. If the virtual file system is initramfs, run the following command to check whether native KVM drivers have been installed:

   lsinitrd /boot/initramfs-`uname -r`.img | grep virtio

   If the virtual file system is initrd, run the following command to check whether native KVM drivers have been installed:

   lsinitrd /boot/initrd-`uname -r` | grep virtio

   Assume that the virtual file system is initramfs. The following command output will be displayed:

   [root@CTU10000xxxxx home]# lsinitrd /boot/initramfs-`uname -r`.img | grep virtio 
   -rwxr--r--   1 root     root        23448 Jul 16 17:53 lib/modules/2.6.32-573.8.1.el6.x86_64/kernel/drivers/block/virtio_blk.ko 
   -rwxr--r--   1 root     root        50704 Jul 16 17:53 lib/modules/2.6.32-573.8.1.el6.x86_64/kernel/drivers/net/virtio_net.ko 
   -rwxr--r--   1 root     root        28424 Jul 16 17:53 lib/modules/2.6.32-573.8.1.el6.x86_64/kernel/drivers/scsi/virtio_scsi.ko 
   drwxr-xr-x   2 root     root            0 Jul 16 17:53 lib/modules/2.6.32-573.8.1.el6.x86_64/kernel/drivers/virtio 
   -rwxr--r--   1 root     root        14544 Jul 16 17:53 lib/modules/2.6.32-573.8.1.el6.x86_64/kernel/drivers/virtio/virtio.ko 
   -rwxr--r--   1 root     root        21040 Jul 16 17:53 lib/modules/2.6.32-573.8.1.el6.x86_64/kernel/drivers/virtio/virtio_pci.ko 
   -rwxr--r--   1 root     root        18016 Jul 16 17:53 lib/modules/2.6.32-573.8.1.el6.x86_64/kernel/drivers/virtio/virtio_ring.ko

   

   If you add built-in drivers to the initrd or initramfs file, the ECS will not be affected. This makes it easy to modify the drivers. However, you cannot check the drivers by running the lsinitrd command. You can run the following command to check whether the drivers are built-in ones in the kernel:

   cat /boot/config-`uname -r` | grep CONFIG_VIRTIO | grep y

Ubuntu and Debian

1. Run the following command to open the modules file:

   vi /etc/initramfs-tools/modules

2. Press i to enter the editing mode and add VirtIO drivers to the /etc/initramfs-tools/modules file (the format varies depending on the OS).

   [root@CTU10000xxxxx ~]#vi /etc/initramfs-tools/modules 
   ...
   # Examples: 
   # 
   # raid1 
   # sd_mOd 
   virtio_blk
   virtio_scsi
   virtio_net
   virtio_pci
   virtio_ring
   virtio

3. Press Esc, enter :wq, and press Enter. The system saves the change and exits the /etc/initramfs-tools/modules file.
4. Run the following command to regenerate initrd:

   update-initramfs -u

5. Run the following command to check whether native KVM drivers have been installed:

   lsinitramfs /boot/initrd.img-`uname -r` |grep virtio

   [root@ CTU10000xxxxx home]# lsinitramfs /boot/initrd.img-`uname -r` |grep virtio 
   lib/modules/3.5.0-23-generic/kernel/drivers/scsi/virtio_scsi.ko

   

   If you add built-in drivers to the initrd or initramfs file, the ECS will not be affected. This makes it easy to modify the drivers. However, you cannot check the drivers by running the lsinitrd command. You can run the following command to check whether the drivers are built-in ones in the kernel:

   [root@ CTU10000xxxxx home]# cat /boot/config-`uname -r` | grep CONFIG_VIRTIO | grep y
   CONFIG_VIRTIO_BLK=y
   CONFIG_VIRTIO_NET=y
   CONFIG_VIRTIO=y
   CONFIG_VIRTIO_RING=y
   CONFIG_VIRTIO_PCI=y
   CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES=y

SUSE and openSUSE (Earlier than SUSE 12 SP1 or openSUSE 13)

SUSE and openSUSE (SUSE 12 SP1)

SUSE and openSUSE (Later than SUSE 12 SP1 or openSUSE 13)

Modify the /etc/dracut.conf file.