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computing:virtmanagerhell [2023/01/02 15:38] oemb1905computing:virtmanagerhell [2026/04/05 00:45] (current) oemb1905
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-To make a VM from the command line, do the following. Note that this recipe assumes you have already created your virtual switch, br0. It also presumes you have already created your virtual disk, and if you have not, simply run ''sudo qemu-img create -f raw new.img 1000G''.+To make a VM from the command line, do the following. Note that this recipe assumes you have already created your virtual switch, br0. It also presumes you have already created your virtual disk, and if you have not, simply run ''sudo qemu-img create -f raw new.img 1000G''Here's a basic block:
  
   sudo virt-install --name=new.img \   sudo virt-install --name=new.img \
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   --location=/mnt/vms/isos/debian-11.4.0-amd64-netinst.iso \   --location=/mnt/vms/isos/debian-11.4.0-amd64-netinst.iso \
   --network bridge:br0   --network bridge:br0
 +
 +Here's a more complex block, that enables trim on vdd, uses a preseed.cfg file to automate install, establishes a custom vnet name, enables the guest agent, and opens a terminal/console inside the shell of the host to manage the install itself:
 +
 +  virt-install --name=domain.com.qcow2 \
 +    --os-variant=debian12 \
 +    --vcpu=2 \
 +    --memory 4096 \
 +    --disk path=/mnt/machine/domain.com.qcow2,driver.discard=unmap \
 +    --check path_in_use=off \
 +    --graphics none \
 +    --location=/mnt/isos/debian-13.1.0-amd64-netinst.iso \
 +    --network bridge:br0,target=domain-com \
 +    --channel unix,target_type=virtio,name=org.qemu.guest_agent.0 \
 +    --initrd-inject=/mnt/configs/${hostname}/preseed.cfg \
 +    --extra-args="auto=true priority=critical preseed/file=/preseed.cfg console=ttyS0,115200n8"
  
 To clone an existing image, do the following: To clone an existing image, do the following:
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   dd if=/dev/urandom of=file bs=4M count=500   dd if=/dev/urandom of=file bs=4M count=500
 +  
 +To create a backup volume inside a guest you create the volume, attach it, and then shell into the guest and format, mount, and create an fstab entry. First, on the hostOS:
 +  
 +  cd /mnt/vms/backups/vm1-backup-dir/
 +  qemu-img create -f qcow2 vm1-backup.qcow2 32G
 +  virsh attach-disk guestOS.qcow2 \
 +    --source /mnt/vms/backups/vm1-backup-dir/vm1-backup \
 +    --target vdb \
 +    --persistent
 +  
 +Then, on the guestOS:
 +  
 +  mkdir /mnt/backup
 +  mkfs.ext4 /dev/vdb
 +  mount -t auto /dev/vdb /mnt/backup
 +  nano /etc/fstab
 +  /dev/vdb /mnt/backup ext4 defaults, 0 0
  
 The rest from here on out is my attempt at resizing an .img virtual disk using tools exclusively from virsh / virt-manager. These are highly risky moves and totally not needed for day to day operations. It was more of a mission I was on and based on a tutorial I used nearly 15 years ago when expanding a Windows VM I used for teaching software that was only on that VM. At any rate, I have only succeeded twice doing this, and often get confused looking at the l00ps. Proceed with caution! The rest from here on out is my attempt at resizing an .img virtual disk using tools exclusively from virsh / virt-manager. These are highly risky moves and totally not needed for day to day operations. It was more of a mission I was on and based on a tutorial I used nearly 15 years ago when expanding a Windows VM I used for teaching software that was only on that VM. At any rate, I have only succeeded twice doing this, and often get confused looking at the l00ps. Proceed with caution!
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   kpartx -d debian10.img   kpartx -d debian10.img
 +  
 +User and group perms:
 +
 +  adduser libvirt-qemu kvm
 +  adduser cockpit-ws kvm
 +  newgrp kvm
 +
 +Add network interface as custom name for easy tracking:
 +
 +<code>
 +  virsh edit domain.com.qcow2
 +  
 +  <interface type='bridge'>
 +    <mac address='11:23:11:7b:99:33'/>
 +    <source bridge='br0'/>
 +    <target dev='domain-com'/>
 +    <model type='virtio'/>
 +    <address type='pci' domain='0x0000' bus='0x01' slot='0x00' function='0x0'/>
 +  </interface>
 +</code>
 +
 +Make sure that Cockpit can access a terminal:
 +
 +<code>
 +  virsh edit domain.com.qcow2
 +  <graphics type='vnc' port='-1' autoport='yes' listen='127.0.0.1'>
 +    <listen type='address' address='127.0.0.1'/>
 +  </graphics>
 +</code>
 +
 +If you don't have video enabled, do the following (also needed for Cockpit Terminal rendering):
 +
 +Option 1 (cirrus):
 +<code>
 + <video>
 +   <model type='cirrus' vram='16384' heads='1' primary='yes'/>
 +   <address type='pci' domain='0x0000' bus='0x10' slot='0x01' function='0x0'/>
 + </video>
 +</code>
 +
 +Option 2 (qxl)
 +<code>
 + <video>
 +   <model type='qxl' ram='65536' vram='65536' vgamem='16384' heads='1' primary='yes'/>
 + </video>
 +</code>
 +
 +Option 3 (use commands)
 +  virt-xml domain.com.qcow2 --add-device --graphics vnc,listen=127.0.0.1
 +  virt-xml domain.com.qcow2 --add-device --video qxl
 +  virsh reboot domain.com.qcow2
 +
 +Add virtiofs mount point. Here's two, note the staggered bus entry of ''0x07'' vs. ''0x08'':
 +
 +<code>
 +  <filesystem type='mount' accessmode='passthrough'>
 +    <driver type='virtiofs'/>
 +    <source dir='/mnt/support1'/>
 +    <target dir='support1'/>
 +    <address type='pci' domain='0x0000' bus='0x07' slot='0x00' function='0x0'/>
 +  </filesystem>
 +  <filesystem type='mount' accessmode='passthrough'>
 +    <driver type='virtiofs'/>
 +    <source dir='/mnt/support2'/>
 +    <target dir='support2'/>
 +    <address type='pci' domain='0x0000' bus='0x08' slot='0x00' function='0x0'/>
 +  </filesystem>
 +</code>
 +
 +Then, inside the VM:
 +
 +  mkdir -p /mnt/support1
 +  mkdir -p /mnt/support2
 +  nano /etc/fstab
 +  support1   /mnt/support1   virtiofs   defaults,_netdev   0 0
 +  support2   /mnt/support2   virtiofs   defaults,_netdev   0 0
 +  
 +If you find ''virsh console domain.com.qcow2'' does not provide a functioning terminal, then run this inside the guest:
 +
 +  sudo systemctl enable serial-getty@ttyS0.service
 +  sudo systemctl start serial-getty@ttyS0.service
 +
 +Migrating an existing VDD and virsh instance ... just dump or copy paste the .xml with ''virsh dump'' or ''virsh edit'', then create a new xml file, typically in ''/var/lib/libvirtd/qemu'', then run:
 +
 +  virsh define host.com.xml
 +  virsh start host.com
 +  
 +You should for sure check the network interface and MAC address, the storage location directory, and obviously run through anything else that might be different on the target migration host.
  
- --- //[[jonathan@haacksnetworking.org|oemb1905]] 2023/01/02 08:37//+ --- //[[alerts@haacksnetworking.org|oemb1905]] 2026/04/05 00:42//
computing/virtmanagerhell.1672673936.txt.gz · Last modified: by oemb1905