The useful and completed references for KVM installation in RHEL 8 and CentOS 8 (including troubleshooting)

KVM_Installation_RHEL8_CentOS8.md

References

• https://computingforgeeks.com/how-to-install-kvm-on-rhel-8
• https://blog.hostonnet.com/opennebula
• https://godleon.github.io/blog/KVM/KVM-Template-And-Snapshot/

Common Problems (Troubleshooting)

• Most of trobuleshottings are also for KVM running in Ubuntu 18.04.

• virsh define node_imei.xml

error: Failed to define domain from node_imei.xml
error: Cannot check QEMU binary /usr/bin/qemu-system-x86_64: No such file or directory

• virsh create node_imei.xml

error: Failed to create domain from node_imei.xml
error: internal error: process exited while connecting to monitor: 2020-07-16T14:37:16.111004Z qemu-system-x86_64: -machine pc-i440fx-bionic,accel=kvm,usb=off,dump-guest-core=off: unsupported machine type
Use -machine help to list supported machines

Solution

• Using virsh capabilities | grep machine to find available machine name

error: Failed to create domain from node_imei.xml
error: internal error: process exited while connecting to monitor: 2020-07-16T14:41:54.254519Z qemu-system-x86_64: -drive file=/root/virtual_smartphone/imei-test/system.img,format=raw,if=none,id=drive-virtio-disk0,readonly=on: Could not open '/root/virtual_smartphone/imei-test/system.img': Permission denied

Solution

• Editing /etc/libvirt/qemu.conf with vim editor.
• Change to line 442 probably.
• Uncomment #user = "root" and #group = "root".
• Uncomment dynamic_ownership = 0 to disable file ownership change.
• systemctl restart libvirtd to restart libvirt daemon service.

error: internal error: process exited while connecting to monitor: 2020-07-16 14:48:12.280+0000: Domain id=1 is tainted: high-privileges
2020-07-16T14:48:12.424833Z qemu-system-x86_64: cannot set up guest memory 'pc.ram': Cannot allocate memory

Solution

• Try to decrease memory or allocate memeories on host OS.

......
<memory unit='KiB'>8388608</memory>
<currentMemory unit='KiB'>8388608</currentMemory>
......

2020-07-16T15:07:48.264787Z qemu-system-x86_64: -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x5,share-rw=on,drive=drive-virtio-disk1,id=virtio-disk1,write-cache=on: Block node is read-only

Solution

• Set current ownership via chown root:root imei-test/* command

guest CPU doesn't match specification: extra features: hypervisor, missing features: tsc_adjust,clflushopt,stibp,ssbd

......
unsupported machine type "pc-i440fx-3.1"
......

Solution

Here are useful commands to check out current CPU features and machine name support:

virsh -c qemu:///system capabilities | grep machine

virsh -c qemu:///system capabilities | grep "feature "

• Fix defined XML file:

......
    <feature policy='require' name='ss'/>
    <feature policy='require' name='tsc_adjust'/>
    <feature policy='require' name='clflushopt'/>
    <feature policy='require' name='stibp'/>
    <feature policy='require' name='ssbd'/>
    <feature policy='require' name='pdpe1gb'/>
    <feature policy='disable' name='mpx'/>
......

Sample CPU Features (propably suggested):

......
<cpu mode='custom' match='exact' check='full'>
    <model fallback='forbid'>Skylake-Client-IBRS</model>
    <vendor>Intel</vendor>
    <feature policy='require' name='vme'/>
    <feature policy='require' name='f16c'/>
    <feature policy='require' name='rdrand'/>
    <feature policy='require' name='hypervisor'/>
    <feature policy='require' name='arat'/>
    <feature policy='require' name='xsaveopt'/>
    <feature policy='require' name='abm'/>
    <feature policy='disable' name='rtm'/>
    <feature policy='disable' name='hle'/>
    <feature policy='disable' name='mpx'/>
    <feature policy='disable' name='rdseed'/>
    <feature policy='disable' name='adx'/>
    <feature policy='disable' name='smap'/>
    <feature policy='disable' name='xsavec'/>
    <feature policy='disable' name='xgetbv1'/>
    <feature policy='disable' name='3dnowprefetch'/>
    <feature policy='disable' name='pcid'/>
    <feature policy='disable' name='erms'/>
    <feature policy='disable' name='invpcid'/>
    <feature policy='disable' name='spec-ctrl'/>
  </cpu>
......

Export VM

• Export XML setting file via virsh dumpxml "machine_name"
• Convert qcow2 file to raw (.img) file

qemu-img convert -f qcow2 -O raw rhel7.5.qcow2 rhel7.5.img

• Convert qcow2 file to raw (.img) file

qemu-img convert -f raw -O qcow2 rhel7.5.img rhel7.5.qcow2

sample.xml

<domain type='kvm'>
  <name>rhel8.1</name>
  <uuid>78b7f58c-1742-4f27-bf31-fc13b0ee3807</uuid>
  <memory unit='KiB'>12288000</memory>
  <currentMemory unit='KiB'>12288000</currentMemory>
  <vcpu placement='static'>2</vcpu>
  <os>
    <type arch='x86_64' machine='pc-i440fx-bionic'>hvm</type>
    <boot dev='hd'/>
  </os>
  <features>
    <acpi/>
    <apic/>
    <vmport state='off'/>
  </features>
  <cpu mode='custom' match='exact' check='partial'>
    <model fallback='allow'>EPYC-IBPB</model>
  </cpu>
  <clock offset='utc'>
    <timer name='rtc' tickpolicy='catchup'/>
    <timer name='pit' tickpolicy='delay'/>
    <timer name='hpet' present='no'/>
  </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/bin/kvm-spice</emulator>
    <disk type='file' device='disk'>
      <driver name='qemu' type='qcow2'/>
      <source file='/data2/rhel7.5.qcow2'/>
      <target dev='vda' bus='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/>
    </disk>
    <disk type='file' device='cdrom'>
      <driver name='qemu' type='raw'/>
      <target dev='hda' bus='ide'/>
      <readonly/>
      <address type='drive' controller='0' bus='0' 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='52:54:00:3a:a0:d6'/>
      <source network='default'/>
      <model type='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
    </interface>
    <serial type='pty'>
      <target type='isa-serial' port='0'>
        <model name='isa-serial'/>
      </target>
    </serial>
    <console type='pty'>
      <target type='serial' port='0'/>
    </console>
    <channel type='unix'>
      <target type='virtio' name='org.qemu.guest_agent.0'/>
      <address type='virtio-serial' controller='0' bus='0' port='1'/>
    </channel>
    <channel type='spicevmc'>
      <target type='virtio' name='com.redhat.spice.0'/>
      <address type='virtio-serial' controller='0' bus='0' port='2'/>
    </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'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x08' function='0x0'/>
    </memballoon>
  </devices>
</domain>