Help Center/ Image Management Service/ User Guide/ Managing Private Images/ Optimizing a Linux Private Image/ Installing Native KVM Drivers

Updated on 2024-04-16 GMT+08:00

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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.

**Table 1** Modifying configuration files for different OSs
OS	Configuration	Reference
CentOS/EulerOS	Take CentOS 7.0 as an example. In the /etc/dracut.conf file, add VirtIO drivers to add_drivers, including virtio_blk, virtio_scsi, virtio_net, virtio_pci, virtio_ring, and virtio. Separate driver names with spaces. Save and exit the /etc/dracut.conf file and run the dracut -f command to generate initrd again.	CentOS and EulerOS
Ubuntu/Debian	In the /etc/initramfs-tools/modules file, add VirtIO drivers, including virtio_blk, virtio_scsi, virtio_net, virtio_pci, virtio_ring, and virtio. Separate driver names with spaces. Save and exit the /etc/initramfs-tools/modules file and run the update-initramfs -u command to generate initrd again.	Ubuntu and Debian
SUSE and openSUSE	If the OS version is earlier than SUSE 12 SP1 or openSUSE 13: In the /etc/sysconfig/kernel file, add VirtIO drivers to INITRD_MODULES="". VirtIO drivers include virtio_blk, virtio_scsi, virtio_net, virtio_pci, virtio_ring, and virtio. Separate driver names with spaces. Run the mkinitrd command to generate initrd again.	SUSE and openSUSE (Earlier than SUSE 12 SP1 or openSUSE 13)
	If the OS version is SUSE 12 SP1: In the /etc/dracut.conf file, add VirtIO drivers to add_drivers. VirtIO drivers include virtio_blk, virtio_scsi, virtio_net, virtio_pci, virtio_ring, and virtio. Separate driver names with spaces. Run the dracut -f command to generate initrd again.	SUSE and openSUSE (SUSE 12 SP1)
	If the OS version is later than SUSE 12 SP1 or openSUSE 13: In the /etc/dracut.conf file, add VirtIO drivers to add_drivers, including virtio_blk, virtio_scsi, virtio_net, virtio_pci, virtio_ring, and virtio. Separate driver names with spaces. Save and exit the /etc/dracut.conf file and run the dracut -f command to generate initrd again.	SUSE and openSUSE (Later than SUSE 12 SP1 or openSUSE 13)

CentOS and EulerOS

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

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" 
....

Press Esc, enter :wq, and press Enter. The system saves the change and exits the /etc/dracut.conf file.
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.

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

Run the following command to open the modules file:
vi /etc/initramfs-tools/modules

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

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

Modify the /etc/sysconfig/kernel file.

Run the following command to modify the /etc/sysconfig/kernel file:
vi /etc/sysconfig/kernel

Add VirtIO drivers to INITRD_MODULES="" (the format of drivers depends on the OS).

SIA10000xxxxx:~ # vi /etc/sysconfig/kernel 
# (like drivers for scsi-controllers, for lvm or reiserfs)
#
INITRD_MODULES="ata_piix ata_generic virtio_blk virtio_scsi virtio_net virtio_pci virtio_ring virtio"

Run the mkinitrd command to generate initrd again.

If the virtual file system is not the default initramfs or initrd, 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 menu.lst or grub.cfg file (/boot/grub/menu.lst, /boot/grub/grub.cfg, or /boot/grub2/grub.cfg).

The following is an example initrd file of SUSE 11 SP4:
```
default 0 
timeout 10 
gfxmenu (hd0,0)/boot/message 
title sles11sp4_001_[_VMX_] 
root (hd0,0) 
kernel /boot/linux.vmx vga=0x314 splash=silent console=ttyS0,115200n8 console=tty0 net.ifnames=0 NON_PERSISTENT_DEVICE_NAMES=1 showopts 
initrd /boot/initrd.vmx 
title Failsafe_sles11sp4_001_[_VMX_] 
root (hd0,0) 
kernel /boot/linux.vmx vga=0x314 splash=silent ide=nodma apm=off noresume edd=off powersaved=off nohz=off highres=off processsor.max+cstate=1 nomodeset x11failsafe console=ttyS0,115200n8 console=tty0 net.ifnames=0 NON_PERSISTENT_DEVICE_NAMES=1 showopts 
initrd /boot/initrd.vmx
```
/boot/initrd.vmx in the initrd line is the initrd file actually used. Run the dracut -f /boot/initrd.vmx command. If the initrd file does not contain the /boot directory, such as /initramfs-xxx, run the dracut -f /boot/initramfs-xxx command.

Run the following command to check whether KVM VirtIO drivers have been installed:

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

SIA10000xxxxx:~ # lsinitrd /boot/initrd-`uname -r` | grep virtio
-rwxr--r-- 1 root root 19248 Jun 22 2012 lib/modules/2.6.32-279.el6.x86_64/kernel/drivers/scsi/virtio_scsi.ko
-rwxr--r-- 1 root root 23856 Jun 22 2012 lib/modules/2.6.32-279.el6.x86_64/kernel/drivers/block/virtio_blk.ko
drwxr-xr-x 2 root root 0 Jul 12 14:53 lib/modules/2.6.32-279.el6.x86_64/kernel/drivers/virtio
-rwxr--r-- 1 root root 15848 Jun 22 2012 lib/modules/2.6.32-279.el6.x86_64/kernel/drivers/virtio/virtio_ring.ko
-rwxr--r-- 1 root root 20008 Jun 22 2012 lib/modules/2.6.32-279.el6.x86_64/kernel/drivers/virtio/virtio_pci.ko
-rwxr--r-- 1 root root 12272 Jun 22 2012 lib/modules/2.6.32-279.el6.x86_64/kernel/drivers/virtio/virtio.ko
-rwxr--r-- 1 root root 38208 Jun 22 2012 lib/modules/2.6.32-279.el6.x86_64/kernel/drivers/net/virtio_net.ko

Restart the ECS.

Run the following command to check whether KVM drivers exist in initrd:

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

SIA10000xxxxx:~ # lsinitrd /boot/initrd-`uname -r` | grep virtio
-rwxr--r-- 1 root root 19248 Jun 22 2012 lib/modules/2.6.32-279.el6.x86_64/kernel/drivers/scsi/virtio_scsi.ko
-rwxr--r-- 1 root root 23856 Jun 22 2012 lib/modules/2.6.32-279.el6.x86_64/kernel/drivers/block/virtio_blk.ko
drwxr-xr-x 2 root root 0 Jul 12 14:53 lib/modules/2.6.32-279.el6.x86_64/kernel/drivers/virtio
-rwxr--r-- 1 root root 15848 Jun 22 2012 lib/modules/2.6.32-279.el6.x86_64/kernel/drivers/virtio/virtio_ring.ko
-rwxr--r-- 1 root root 20008 Jun 22 2012 lib/modules/2.6.32-279.el6.x86_64/kernel/drivers/virtio/virtio_pci.ko
-rwxr--r-- 1 root root 12272 Jun 22 2012 lib/modules/2.6.32-279.el6.x86_64/kernel/drivers/virtio/virtio.ko
-rwxr--r-- 1 root root 38208 Jun 22 2012 lib/modules/2.6.32-279.el6.x86_64/kernel/drivers/net/virtio_net.ko

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

SUSE and openSUSE (SUSE 12 SP1)

Modify the /etc/dracut.conf file.

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

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+="ata_piix ata_generic virtio_blk virtio_scsi virtio_net virtio_pci virtio_ring virtio"

Press Esc, enter :wq, and press Enter. The system saves the change and exits the /etc/dracut.conf file.
Run the following command to regenerate initrd:
dracut -f /boot/initramfs-File name

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.
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

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

Modify the /etc/dracut.conf file.

Take SUSE Linux Enterprise Server 12 SP2 (x86_64) as an example.

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

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+="ata_piix ata_generic virtio_blk virtio_scsi virtio_net virtio_pci virtio_ring virtio"

Press Esc, enter :wq, and press Enter. The system saves the change and exits the /etc/dracut.conf file.
Run the following command to regenerate initrd:
dracut -f /boot/initramfs-File name

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.

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 initrd. The following command output will be displayed:

sluo-ecs-30dc:~ # lsinitrd /boot/initrd-`uname -r` | grep virtio
-rw-r--r-- 1 root root 29335 Oct 26 2016 lib/modules/4.4.21-69-default/kernel/drivers/block/virtio_blk.ko
-rw-r--r-- 1 root root 57007 Oct 26 2016 lib/modules/4.4.21-69-default/kernel/drivers/net/virtio_net.ko
-rw-r--r-- 1 root root 32415 Oct 26 2016 lib/modules/4.4.21-69-default/kernel/drivers/scsi/virtio_scsi.ko
drwxr-xr-x 2 root root 0 Sep 28 10:21 lib/modules/4.4.21-69-default/kernel/drivers/virtio
-rw-r--r-- 1 root root 19623 Oct 26 2016 lib/modules/4.4.21-69-default/kernel/drivers/virtio/virtio.ko
-rw-r--r-- 1 root root 38943 Oct 26 2016 lib/modules/4.4.21-69-default/kernel/drivers/virtio/virtio_pci.ko
-rw-r--r-- 1 root root 24431 Oct 26 2016 lib/modules/4.4.21-69-default/kernel/drivers/virtio/virtio_ring.ko