Black Screen only in KVM, trying to install CentOS7

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TrundleRumble
Posts: 5
Joined: 2018/08/01 06:55:11

Black Screen only in KVM, trying to install CentOS7

Post by TrundleRumble » 2018/08/01 07:05:04

Hi, just getting into CentOS trying to setup to study for RedHat certifications, can't even get the setup right lol.

I have a centOS7 physical host, and installed KVM, Qemu, libvirt, all that. I have downloaded the centos7 dvd iso, and when creating a brand new VM and tyring to boot off that iso (attached as dvd drive) all I get is a black screen. I have tried the dvd and the everything .iso, and switched the video from cirrus to vga.

I have confirmed other VMs screens work without issue. Ubuntu installer, another VM I have I moved over, and even the centOS 6 ISO! Its only centos7 with the issue. I also tried using vnc to connect directly to the VM, same thing black screen. Sending ctrl alt f1-through 12 does nothing.

Im wondering if this has something to do with boot mode. When I installed centos7 on the physical host, I was selecting my USB drive with the image in bios to boot... then would select centOS and just get a kernel panic output. It only worked when I selected my USB drive with the (EFI) label next to it, then the slection screen looked a little different but worked.

My Physical host info can be found here: https://pastebin.com/ZcmZ2TWb

The XML for the current VM is here:


Edit: The XML below did not have the .iso attached, it detachtes I guess after the first power down. However that was not the issue I found the issue. The screen is blank if I give any more than 1 cpu to the vm, So I guess my question is why would that be? Going to install and see if I cna increase it later.

Code: Select all

<domain type='qemu'>
  <name>centos7.0</name>
  <uuid>39a19eff-3367-4b05-8b35-73f555d0c874</uuid>
  <memory unit='KiB'>4194304</memory>
  <currentMemory unit='KiB'>4194304</currentMemory>
  <vcpu placement='static'>4</vcpu>
  <os>
    <type arch='x86_64' machine='pc-i440fx-rhel7.0.0'>hvm</type>
    <boot dev='hd'/>
  </os>
  <features>
    <acpi/>
    <apic/>
  </features>
  <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/libexec/qemu-kvm</emulator>
    <disk type='file' device='disk'>
      <driver name='qemu' type='qcow2'/>
      <source file='/var/lib/libvirt/images/centos7.0-1.qcow2'/>
      <target dev='vda' bus='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x06' 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='0x04' function='0x7'/>
    </controller>
    <controller type='usb' index='0' model='ich9-uhci1'>
      <master startport='0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0' multifunction='on'/>
    </controller>
    <controller type='usb' index='0' model='ich9-uhci2'>
      <master startport='2'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x1'/>
    </controller>
    <controller type='usb' index='0' model='ich9-uhci3'>
      <master startport='4'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' 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='0x05' function='0x0'/>
    </controller>
    <interface type='direct'>
      <mac address='52:54:00:27:9a:1e'/>
      <source dev='enp31s0' mode='bridge'/>
      <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>
    <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='vnc' port='-1' autoport='yes'>
      <listen type='address'/>
    </graphics>
    <video>
      <model type='cirrus' vram='16384' heads='1' primary='yes'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
    </video>
    <memballoon model='virtio'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/>
    </memballoon>
  </devices>
</domain>

CentOS 6.0 works right away. Would it be best to install that and upgrade? I thought upgrading centOS meant just re-imaging anyway but not sure.

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TrevorH
Site Admin
Posts: 33202
Joined: 2009/09/24 10:40:56
Location: Brighton, UK

Re: Black Screen only in KVM, trying to install CentOS7

Post by TrevorH » 2018/08/01 13:04:35

Why are you not using virt-install?
The future appears to be RHEL or Debian. I think I'm going Debian.
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 and 6 are deadest, do not use them.
Use the FAQ Luke

TrundleRumble
Posts: 5
Joined: 2018/08/01 06:55:11

Re: Black Screen only in KVM, trying to install CentOS7

Post by TrundleRumble » 2018/10/18 06:15:02

Because I have never used that, but also the trouble is coming from installing centOS on the VM made through virtual machine manager. Would I not have the same issue if I had defined the VM via virt-install?

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