linux - 无法获取 libvirt 域的所有内存统计信息

Question

我在使用虚拟机( guest Windows 7、x86_64)时遇到了一些问题，该虚拟机在 qemu-kvm 下运行并由 libvirt 管理(主要从 virt-manager 创建和运行)。问题是我无法通过运行获得完整的内存统计信息

virsh -c qemu:///system dommemstat win7

或通过调用

virDomainMemoryStats(...)

来自 C++ 代码(据我所知，或多或少是相同的东西)。我还测试了来自 libvirt aplication dev guide 的 libvirt 第 35 个示例.这真的让我很担心，因为现在我在项目下工作，旨在为 vm 自动设置最佳内存大小，因此我的代码中需要它们。

我从 virsh 得到的唯一输出是

actual 4194304
last_update 1500404513
rss 4161676

在网上搜索后，我发现这些是统计信息，libvirt 可以在不应用于 ballooning 驱动程序的情况下获得。但是我已经在 Windows 中安装了 VirtIO ballooning 驱动程序，系统声称它正在运行。我真的不知道，如何找出 qemu 是否意识到它(为您的想法打开)。

我还发现我需要在系统xml中设置统计时间段，我已经设置了但什么也没给。我还发现 qemu 使用一些“qom-get”脚本来实际测量统计数据，但我不能使用它

virsh # qemu-monitor-command 1 --hmp "qom-get"

(输出该命令未知)并且我在我的 PATH 中看不到它。此外，pacman -Fo qom-get 和 pkgfile qom-get 什么也没给出。我的主机系统是 Arch Linux。 win7.xml的内容是

<domain type='kvm'>
  <name>win7</name>
  <uuid>438145c1-a2df-4c86-96d6-2bf7b379d70b</uuid>
  <memory unit='KiB'>4194304</memory>
  <currentMemory unit='KiB'>4194304</currentMemory>
  <vcpu placement='static' current='2'>4</vcpu>
  <os>
    <type arch='x86_64' machine='pc-i440fx-2.9'>hvm</type>
    <boot dev='hd'/>
  </os>
  <features>
    <acpi/>
    <apic/>
    <hyperv>
      <relaxed state='on'/>
      <vapic state='on'/>
      <spinlocks state='on' retries='8191'/>
    </hyperv>
    <vmport state='off'/>
  </features>
  <cpu mode='custom' match='exact' check='partial'>
    <model fallback='allow'>Broadwell-noTSX</model>
  </cpu>
  <clock offset='localtime'>
    <timer name='rtc' tickpolicy='catchup'/>
    <timer name='pit' tickpolicy='delay'/>
    <timer name='hpet' present='no'/>
    <timer name='hypervclock' present='yes'/>
  </clock>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>destroy</on_crash>
  <pm>
    <suspend-to-mem enabled='no'/>
    <suspend-to-disk enabled='no'/>
  </pm>
  <devices>
    <emulator>/usr/sbin/qemu-system-x86_64</emulator>
    <disk type='file' device='disk'>
      <driver name='qemu' type='qcow2'/>
      <source file='/var/lib/libvirt/images/win7.qcow2'/>
      <target dev='hda' bus='ide'/>
      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
    </disk>
    <disk type='file' device='cdrom'>
      <driver name='qemu' type='raw'/>
      <target dev='hdb' bus='ide'/>
      <readonly/>
      <address type='drive' controller='0' bus='0' target='0' unit='1'/>
    </disk>
    <disk type='file' device='cdrom'>
      <driver name='qemu' type='raw'/>
      <source file='/usr/share/virtio/virtio-win.iso'/>
      <target dev='hdc' bus='ide'/>
      <readonly/>
      <address type='drive' controller='0' bus='1' target='0' unit='0'/>
    </disk>
    <controller type='usb' index='0' model='ich9-ehci1'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x7'/>
    </controller>
    <controller type='usb' index='0' model='ich9-uhci1'>
      <master startport='0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0' multifunction='on'/>
    </controller>
    <controller type='usb' index='0' model='ich9-uhci2'>
      <master startport='2'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x1'/>
    </controller>
    <controller type='usb' index='0' model='ich9-uhci3'>
      <master startport='4'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x2'/>
    </controller>
    <controller type='pci' index='0' model='pci-root'/>
    <controller type='ide' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
    </controller>
    <controller type='virtio-serial' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
    </controller>
    <interface type='network'>
      <mac address='52:54:00:9d:4e:85'/>
      <source network='default'/>
      <model type='rtl8139'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
    </interface>
    <serial type='pty'>
      <target port='0'/>
    </serial>
    <console type='pty'>
      <target type='serial' port='0'/>
    </console>
    <channel type='spicevmc'>
      <target type='virtio' name='com.redhat.spice.0'/>
      <address type='virtio-serial' controller='0' bus='0' port='1'/>
    </channel>
    <input type='tablet' bus='usb'>
      <address type='usb' bus='0' port='1'/>
    </input>
    <input type='mouse' bus='ps2'/>
    <input type='keyboard' bus='ps2'/>
    <graphics type='spice' autoport='yes'>
      <listen type='address'/>
      <image compression='off'/>
    </graphics>
    <sound model='ich6'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
    </sound>
    <video>
      <model type='qxl' ram='65536' vram='65536' vgamem='16384' heads='1' primary='yes'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
    </video>
    <redirdev bus='usb' type='spicevmc'>
      <address type='usb' bus='0' port='2'/>
    </redirdev>
    <redirdev bus='usb' type='spicevmc'>
      <address type='usb' bus='0' port='3'/>
    </redirdev>
    <memballoon model='virtio'>
      <stats period='10'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/>
    </memballoon>
  </devices>
</domain>

我肯定错过了什么，但我看不到什么。任何人都可以给我任何有用的链接或指南吗？我真的很感激。

这是 question on Arch Linux newbie forum 的副本.如果有人会给出适当的答案，我会与其他网站分享。

============================================= =

更新。气球正在工作:我可以做这样的事情

virsh # qemu-monitor-command win7 --hmp "info balloon"
balloon: actual=4096
virsh # qemu-monitor-command win7 --hmp "balloon 2048"
virsh # qemu-monitor-command win7 --hmp "info balloon"
balloon: actual=2048

但是 qom-get 不行:

virsh # qemu-monitor-command windows7 '{ "execute": "qom-get",  "arguments": { "path": "/machine/peripheral/balloon0",  "property": "guest-stats" } }'
{"return":{"stats":{"stat-swap-out":-1,"stat-available-memory":-1,"stat-free-memory":-1,"stat-minor-faults":-1,"stat-major-faults":-1,"stat-total-memory":-1,"stat-swap-in":-1},"last-update":1500639136},"id":"libvirt-396"}

非常感谢您的帮助。

Answer 1

问题是 Balloon 服务没有正确安装。如果您遇到同样的问题，可能的解决方案是打开命令行，转到带有 VirtIO 驱动程序的 CD-ROM，转到 Balloon 目录和更深的目录，具体取决于您的系统和体系结构。当您在 amd64 (x86) 目录中时，键入

blnsrv.exe -i

服务应该会自行安装。之后问题就会消失(至少，这对我有用)。