libvirt

virt-manger¶

图形化界面

virsh¶

命令行工具

导出虚拟机配置，并定义新虚拟机¶

virsh dumpxml <domain> > file.xml

#编辑file.xml中的uuid，不能和其它重复。再编辑name
virsh define file.xml

qemu-img¶

复制 image(复制稀疏文件)¶

kvm virtualization - What is fastest way to copy a sparse file? What method results in the smallest file? - Server Fault

Via cp - best speed

cp --sparse=always srcFile dstFile
Performance Notes:
    Copied 200GB max/16GB actual VM as 200GB max/26GB actual, bloat: 10GB
    Copy time: 1:02 (mm:ss)

Via dd - best overall performer

dd if=srcFile of=dstFile iflag=direct oflag=direct bs=4M conv=sparse
Performance Notes:
    Copied 200GB max/16GB actual VM as 200GB max/21GB actual, bloat: 5GB
    Copy time: 2:02 (mm:ss)

Via virt-sparsify - best size

virt-sparsify srcFile dstFile
    Copied 200GB max/16GB actual VM as 200GB max/16GB actual, bloat: 0
    Copy time: 17:37 (mm:ss)

cp¶

cp --sparse=always

By default, sparse SOURCE files are detected by a crude heuristic and the corresponding DEST file is made sparse as well. That is the behavior selected by --sparse=auto. Specify --sparse=always to create a sparse DEST file whenever the SOURCE file contains a long enough sequence of zero bytes. Use --sparse=never to inhibit creation of sparse files.

virt-sparsify¶

virt-sparsify (libguestfs.org)

支持多种文件系统。Virt-sparsify can locate and sparsify free space in most filesystems (eg. ext2/3/4, btrfs, NTFS, etc.), and also in LVM physical volumes.
可以将 raw 格式转换为 qcow2 格式

发现一个优点同时也是缺点。virt-sparsify 复制后会清除现有文件的 0 元素，使得文件变小，但同时也会导致 snapshot 记录消失

使用注意：

使用前关闭虚拟机
在删除源镜像前检查
需要 2x 的空间（1 tmp + 1 destination）（最差情况，实际远小于该值）
- virt-sparsify ≥ 1.26 支持 in-place 参数，避免了大量空间的使用。

sudo apt install guestfs-tools
virt-sparsify ori.img new.img

指定 tmp 目录：--tmp my_tmp_folder。不支持--in-place
显示更多信息：-v

复制远程 sparese 文件¶

Sparse Files | Syed Ali

scp’ is not sparse aware and if you use scp to copy a file that is spare it will take up “more” room on the destination host. Instead if you use rsync with -S option, spare files will be maintained as sparse.

rsync -aPS Tianyi:/mnt/Disk1/default.img Backup/

增大 image 大小¶

qemu-img resize <image> +500G

然后在 windows 中分配空间

减小 image 大小¶

要复杂一些参考：Resizing KVM qcow2 images - mauBlog (maunium.net)

overlay¶

qemu-img create -f qcow2 -F qcow2 -b base.qcow2 overlay.qcow2

合并 overlay¶

参考：Qemu: Merge snapshot and backing file into standalone disk | by Praveen Kumar | Medium

如果 B 的 base 是 A，合并是将 B 合并到基镜像中。因此最好备份基镜像。

qemu-img commit overlay.qcow2

变基¶

qemu-img rebase -F qcow2 -f qcow2 -b base.qcow2 overlay.qcow2

convert¶

qemu-img convert disk-life.qcow2 /mnt/VM-Pool/disk-life.raw

时间巨长。40G 花了 30 分钟。并且期间 zfs 的系统无妨使用。

QEMU agent¶

用于控制 windows 虚拟机关机，休眠 (domsuspend)

参考：

参考的都太复杂了，实际操作如下（还没验证效果）：

验证了效果，虚拟机关不掉，一直在 running，只能通过 virsh destory 才能强行关掉。

windows 虚拟机内下载并安装 https://fedorapeople.org/groups/virt/virtio-win/direct-downloads/archive-virtio/ https://fedorapeople.org/groups/virt/virtio-win/direct-downloads/archive-qemu-ga/

virt-manger 中添加 channel，选择 qemu-agent，其余会自动配置

热插拔 usb¶

olavmrk/usb-libvirt-hotplug: Script to attach and detach USB devices from libvirt virtual machines based on udev rules. (github.com)

udev: udev - ArchWiki (archlinux.org)

udev(7) — Arch manual pages (archlinux.org)

ID_VENDOR_ID=0a12
ID_MODEL_ID=0001
/devices/pci0000:00/0000:00:08.1/0000:0a:00.3/usb3/3-3/3-3.4 (usb)

SUBSYSTEM=="usb",DEVPATH=="/devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.2",RUN+="/opt/usb-libvirt-hotplug/usb-libvirt-hotplug.sh testvm-01"
SUBSYSTEM=="usb",ID_VENDOR_ID=="0a12",ID_MODEL_ID="0001",RUN+="/opt/usb-libvirt-hotplug/usb-libvirt-hotplug.sh win10"

KERNEL=="video[0-9]*", SUBSYSTEM=="video4linux", SUBSYSTEMS=="usb", ATTRS{idVendor}=="1de1", ATTRS{idProduct}=="f105", RUN+="/opt/usb-libvirt-hotplug/usb-libvirt-hotplug.sh win10"
# bluetooth
SUBSYSTEMS=="usb", ATTRS{idVendor}=="0a12", ATTRS{idProduct}=="0001", RUN+="/opt/usb-libvirt-hotplug/usb-libvirt-hotplug.sh win10"
# mouse
SUBSYSTEMS=="usb", ATTRS{idVendor}=="30fa", ATTRS{idProduct}=="0400", RUN+="/opt/usb-libvirt-hotplug/usb-libvirt-hotplug.sh win10"
# keyboard
SUBSYSTEMS=="usb", ATTRS{idVendor}=="1a81", ATTRS{idProduct}=="2039", RUN+="/opt/usb-libvirt-hotplug/usb-libvirt-hotplug.sh win10"

监听 usb 设备
- 拔掉会出现 unbind, remove 事件
- 插入会出现 add, change, bind 事件

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

UDEV  [262962.917716] unbind   /devices/pci0000:00/0000:00:01.2/0000:02:00.0/usb1/1-3 (usb)
ACTION=unbind
DEVPATH=/devices/pci0000:00/0000:00:01.2/0000:02:00.0/usb1/1-3
SUBSYSTEM=usb
DEVNAME=/dev/bus/usb/001/009
DEVTYPE=usb_device
PRODUCT=1de1/f105/409
TYPE=239/2/1
BUSNUM=001
DEVNUM=009
SEQNUM=7429
USEC_INITIALIZED=261113847055
ID_PATH=pci-0000:02:00.0-usb-0:3
ID_PATH_TAG=pci-0000_02_00_0-usb-0_3
MAJOR=189
MINOR=8

UDEV  [262890.680932] bind     /devices/pci0000:00/0000:00:08.1/0000:0a:00.3/usb3/3-3/3-3.4 (usb)
ACTION=bind
DEVPATH=/devices/pci0000:00/0000:00:08.1/0000:0a:00.3/usb3/3-3/3-3.4
SUBSYSTEM=usb
DEVNAME=/dev/bus/usb/003/023
DEVTYPE=usb_device
DRIVER=usb
PRODUCT=a12/1/8891
TYPE=224/1/1
BUSNUM=003
DEVNUM=023
SEQNUM=7414
USEC_INITIALIZED=262890673093
ID_VENDOR=0a12
ID_VENDOR_ENC=0a12
ID_VENDOR_ID=0a12
ID_MODEL=CSR8510_A10
ID_MODEL_ENC=CSR8510\x20A10
ID_MODEL_ID=0001
ID_REVISION=8891
ID_SERIAL=0a12_CSR8510_A10
ID_BUS=usb
ID_USB_INTERFACES=:e00101:
ID_VENDOR_FROM_DATABASE=Cambridge Silicon Radio, Ltd
ID_MODEL_FROM_DATABASE=Bluetooth Dongle (HCI mode)
ID_PATH=pci-0000:0a:00.3-usb-0:3.4
ID_PATH_TAG=pci-0000_0a_00_3-usb-0_3_4
MAJOR=189
MINOR=278

休眠¶

OVMF 不支持 S4(sleep to disk, hibernation) https://listman.redhat.com/archives/vfio-users/2017-September/msg00011.html

PS C:\Windows\system32>  powercfg /A
此系统上没有以下睡眠状态:
    待机 (S1)
        系统固件不支持此待机状态。
        虚拟机监控程序不支持此待机状态。

    待机 (S2)
        系统固件不支持此待机状态。
        虚拟机监控程序不支持此待机状态。

    待机 (S3)
        虚拟机监控程序不支持此待机状态。

    休眠
        该虚拟机监控程序不支持休眠。

    待机(S0 低电量待机)
        系统固件不支持此待机状态。

    混合睡眠
        待机(S3)不可用。
        休眠不可用。
        虚拟机监控程序不支持此待机状态。

    快速启动
        休眠不可用。

https://www.linux-kvm.org/page/PowerManagement

libvirt 开启休眠选项：

<pm>
  <suspend-to-disk enabled='yes'/>
  <suspend-to-mem enabled='yes'/>
</pm>

These elements enable ('yes') or disable ('no') BIOS support for S3 (suspend-to-mem) and S4 (suspend-to-disk) ACPI sleep states. If nothing is specified, then the hypervisor will be left with its default value. Note: This setting cannot prevent the guest OS from performing a suspend as the guest OS itself can choose to circumvent the unavailability of the sleep states (e.g. S4 by turning off completely).

➜ VM-Pool sudo virsh domtime win10-base error: argument unsupported: QEMU guest agent is not configured