kvm - SCSI 裝置(hotplug usb/disk)

最後更新: 2017-09-13

介紹

attach-disk

Passthrough disk

Host USB: attach-device

 


SCSI 裝置(attach-disk)

 

Hot attach disk: raw

virsh attach-disk domain-name --source /path/to/disk/image/file --target sdb

                                               等同於

virsh attach-disk domain-name  /path/to/disk/image/file  sdb

會建立的 XML:

<disk type='file' device='disk'>
<driver name='qemu' type='raw' cache='writeback'/>

Qcow2 image disk 裝置:

qemu-img create -f qcow2 vdb.qcow2 5g

virsh attach-disk domain-name /path/to/another/image vdb  --subdriver qcow2

會建立的 XML:

<disk type='file' device='disk'>
<driver name='qemu' type='qcow2'/>

其他選項:

--persistent                                     # 會寫到 config file
--shareable                                     # Shareable between domains. Default: No
--mode  <readonly | shareable>     
--type <disk | cdrom>                    # Target device type. Default: virtio
--driver <tap | qemu>                     # Default: qemu

P.S.

沒有 --persistent 時, Domain destory/start 後 disk 會 detact 左

Checking

domblklist centos6

Target     Source
------------------------------------------------
vda        /ssd/iredmail/centos6.qcow2
vdb        /ssd/iredmail/vdb.qcow2

Detach

detach-disk vmname disk

 



Passthrough disk

 

XML

<disk type='block' device='disk'>
  <driver name='qemu' type='raw'/>
  <source dev='/dev/sdc'/>
  <target dev='vda' bus='virtio'/>
</disk>

P.S.

避免 mount 錯 Disk

use /dev/disk/by-id/ as source

對於不支援 virtio 的 system 要用 sata

sata XML:

<target dev='sda' bus='sata'/>

即使 <target dev='sdX' bus='virtio'/>, lsblk 仍會見到是 vdX

Example

<disk type='block' device='disk'>
  <driver name='qemu' type='raw'/>
  <source dev='/dev/disk/by-id/ata-WDC_WD2002FAEX-007BA0_WD-WMAWP0494690'/>
  <target dev='sdg' bus='sata'/>
</disk>

 


USB_DISK_IMAGE

 

s2008.xml

<controller type='scsi'/>
    <controller type='scsi' index='0'>
    <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/>
</controller>

# dd if=/dev/zero of=/kvm/s2008/usbdisk.raw bs=1M count=64

# virsh attach-disk s2008 /kvm/s2008/usbdisk.raw sda

P.S.

直接 attach-disk 上 s2008 而它又不是 --type cdrom 時, 那 VM 是會死的 !!

s2008.xml

<devices>
    .............
    <controller type='scsi' model='lsilogic'/>
</devices>

scsi-disk.xml

<disk type='file' device='disk'>
      <driver name='qemu' type='raw'/>
      <source file='/kvm/s2008/usbdisk.raw'/>
      <target dev='sda' bus='scsi'/>
       <address type='drive' controller='0' bus='0' unit='0'/>
</disk>

要用 SCSI archicture: SCSI supports hot plugging

  • vdX, the disk is connected to a virtio controller
  • sdX, the disk is connected to a scsi controller
  • hdX, the disk is connected to an IDE controller

# virsh attach-device s2008 scsi-disk.xml

 



Host USB: attach-device

 

lsusb

Bus 002 Device 003: ID 0411:01f0 BUFFALO INC. (formerly MelCo., Inc.)

mkdir /etc/libvirt/HotPlug

vim /etc/libvirt/HotPlug/BackupDisk.xml

<hostdev mode='subsystem' type='usb'>
  <source>
    <vendor id='0x0411'/>
    <product id='0x01f0'/>
  </source>
</hostdev>

掛載 USB 儲存裝置:

# 掛載

virsh attach-device xpenology /etc/libvirt/HotPlug/BackupDisk.xml

Device attached successfully

# 查看

virsh qemu-monitor-command xpenology --hmp 'info usb'

Device 0.2, Port 1, Speed 480 Mb/s, Product HD-LBU3

OR

virsh dumpxml xpenology

<hostdev mode='subsystem' type='usb' managed='no'>
  <source>
    <vendor id='0x0411'/>
    <product id='0x01f0'/>
    <address bus='2' device='3'/>
  </source>
  <alias name='hostdev0'/>
</hostdev>

卸載 USB 儲存裝置:

virsh detach-device xpenology /etc/libvirt/HotPlug/BackupDisk.xml

Device detached successfully

managed

There are two modes in which a PCI device can be attached, "managed" or "unmanaged" mode,

although at time of writing only KVM supports "managed" mode attachment.

In managed mode, the configured device will be automatically detached from the host OS drivers when the guest is started,

and then re-attached when the guest shuts down.

In unmanaged mode, the device must be explicit detached ahead of booting the guest.

The guest will refuse to start if the device is still attached to the host OS.

The libvirt 'Node Device' APIs provide a means to detach/reattach PCI devices from/to host drivers.

Alternatively the host OS may be configured to blacklist the PCI devices used for guest, so that they never get attached to host OS drivers.

 

In both modes, the virtualization technology will always perform a reset on the device before starting a guest, and after the guest shuts down.

This is critical to ensure isolation between host and guest OS. There are a variety of ways in which a PCI device can be reset.

Some reset techniques are limited in scope to a single device/function, while others may affect multiple devices at once.

Auto mount by udev rule:

/etc/udev/rules.d/90-BackupDisk.rules

ACTION=="add", \
  SUBSYSTEM=="usb", \
  SYSFS{idVendor}=="0411", \
  SYSFS{idProduct}=="01f0", \
  RUN+="/usr/bin/virsh attach-device xpenology /etc/libvirt/HotPlug/BackupDisk.xml"

ACTION=="remove", \
  SUBSYSTEM=="usb", \
  SYSFS{idVendor}=="0411", \
  SYSFS{idProduct}=="01f0", \
  RUN+="/usr/bin/virsh detach-device xpenology /etc/libvirt/HotPlug/BackupDisk.xml"

service udev reload

Device info.

In order to determine what attributes to use for matching, you can use udevadm monitor:

udevadm monitor --property --udev --subsystem-match=usb/usb_device

UDEV  [21887.137896] add      /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2 (usb)
ACTION=add
BUSNUM=002
DEVNAME=/dev/bus/usb/002/003
DEVNUM=003
DEVPATH=/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2
DEVTYPE=usb_device
ID_BUS=usb
ID_MODEL=HD-LBU3
ID_MODEL_ENC=HD-LBU3
ID_MODEL_ID=01f0
ID_REVISION=0001
ID_SERIAL=BUFFALO_HD-LBU3_010920005E15
ID_SERIAL_SHORT=010920005E15
ID_USB_INTERFACES=:080650:
ID_VENDOR=BUFFALO
ID_VENDOR_ENC=BUFFALO
ID_VENDOR_FROM_DATABASE=BUFFALO INC. (formerly MelCo., Inc.)
ID_VENDOR_ID=0411
MAJOR=189
MINOR=130
PRODUCT=411/1f0/1
SEQNUM=2298
SUBSYSTEM=usb
TYPE=0/0/0
USEC_INITIALIZED=887053724

* If you want to match a specific USB port, you will probably want to use the DEVPATH attribute.

* To match a specific device instead, use the ID_VENDOR_ID and ID_MODEL_ID attributes.

Note:

It may be tempting to use ATTR{busnum} and ATTR{devpath} to match the USB bus and port number.

However, those attributes are only available when the device is added, and not when the device is removed.

This leads to the device not being properly removed from the VM.

 


List Support Device

 

-device driver[,prop[=value][,...]]
                add device (based on driver)
                prop=value,... sets driver properties
                use '-device help' to print all possible drivers
                use '-device driver,help' to print all possible properties

kvm -device help |& grep scsi

kvm -device scsi-disk,help

name "scsi-disk", bus SCSI, desc "virtual SCSI disk or CD-ROM (legacy)"

name "megasas", bus PCI, desc "LSI MegaRAID SAS 1078"
name "megasas-gen2", bus PCI, desc "LSI MegaRAID SAS 2108"
name "mptsas1068", bus PCI, desc "LSI SAS 1068"

 


Allow libvirt full access USB

 

log

[1387980.187472] audit: type=1400 audit(1496842729.126:405): apparmor="DENIED" operation="open" profile="libvirt-78c13701-b7f0-4e43-bcd2-fcca1c8ee3a7" name="/run/udev/data/+usb:8-0:1.0" pid=24884 comm="qemu-system-x86" requested_mask="r" denied_mask="r" fsuid=108 ouid=0

# config apparmor

/etc/apparmor.d/abstractions/libvirt-qemu

# For hostdev access. The actual devices will be added dynamically
/sys/bus/usb/devices/ rw,
/dev/bus/usb/*/[0-9]* rw,
/sys/devices/**/usb[0-9]*/** rw,
/run/udev/** rw,

# re-start service

/etc/init.d/apparmor restart
/etc/init.d/libvirt-bin restart