14.5. Managing virtual machine storage volumes using the CLI

Procédure

1. Use the virsh vol-list command to list the storage volumes in a specified storage pool.

   # virsh vol-list --pool RHEL-Storage-Pool --details
    Name                Path                                               Type   Capacity  Allocation
   ---------------------------------------------------------------------------------------------
    .bash_history       /home/VirtualMachines/.bash_history       file  18.70 KiB   20.00 KiB
    .bash_logout        /home/VirtualMachines/.bash_logout        file    18.00 B    4.00 KiB
    .bash_profile       /home/VirtualMachines/.bash_profile       file   193.00 B    4.00 KiB
    .bashrc             /home/VirtualMachines/.bashrc             file   1.29 KiB    4.00 KiB
    .git-prompt.sh      /home/VirtualMachines/.git-prompt.sh      file  15.84 KiB   16.00 KiB
    .gitconfig          /home/VirtualMachines/.gitconfig          file   167.00 B    4.00 KiB
    RHEL_Volume.qcow2   /home/VirtualMachines/RHEL8_Volume.qcow2  file  60.00 GiB   13.93 GiB

2. Use the virsh vol-info command to list the storage volumes in a specified storage pool.

   # vol-info --pool RHEL-Storage-Pool --vol RHEL_Volume.qcow2
   Name:           RHEL_Volume.qcow2
   Type:           file
   Capacity:       60.00 GiB
   Allocation:     13.93 GiB

Procédure

1. Create a storage volume using the virsh vol-create-as command. For example, to create a 20 GB qcow2 volume based on the guest-images-fs storage pool:

   # virsh vol-create-as --pool guest-images-fs --name vm-disk1 --capacity 20 --format qcow2

   Important: Specific storage pool types do not support the virsh vol-create-as command and instead require specific processes to create storage volumes:

   • iSCSI-based - Prepare the iSCSI LUNs in advance on the iSCSI server.
   • Multipath-based - Use the multipathd command to prepare or manage the multipath.
   • vHBA-based - Prepare the fibre channel card in advance.

2. Create an XML file, and add the following lines in it. This file will be used to add the storage volume as a disk to a VM.

   <disk type='volume' device='disk'>
       <driver name='qemu' type='qcow2'/>
       <source pool='guest-images-fs' volume='vm-disk1'/>
       <target dev='hdk' bus='ide'/>
   </disk>

   This example specifies a virtual disk that uses the vm-disk1 volume, created in the previous step, and sets the volume to be set up as disk hdk on an ide bus. Modify the respective parameters as appropriate for your environment.

   Important: With specific storage pool types, you must use different XML formats to describe a storage volume disk.

   • For multipath-based pools:

     <disk type='block' device='disk'>
     <driver name='qemu' type='raw'/>
     <source dev='/dev/mapper/mpatha' />
     <target dev='sda' bus='scsi'/>
     </disk>

   • For RBD-based storage pools:

       <disk type='network' device='disk'>
         <driver name='qemu' type='raw'/>
         <source protocol='rbd' name='pool/image'>
           <host name='mon1.example.org' port='6321'/>
         </source>
         <target dev='vdc' bus='virtio'/>
       </disk>

3. Use the XML file to assign the storage volume as a disk to a VM. For example, to assign a disk defined in ~/vm-disk1.xml to the testguest1 VM:

   # attach-device --config testguest1 ~/vm-disk1.xml

Procédure

1. Use the virsh vol-list command to list the storage volumes in a specified storage pool.

   # virsh vol-list --pool RHEL-SP
    Name                 Path
   ---------------------------------------------------------------
    .bash_history        /home/VirtualMachines/.bash_history
    .bash_logout         /home/VirtualMachines/.bash_logout
    .bash_profile        /home/VirtualMachines/.bash_profile
    .bashrc              /home/VirtualMachines/.bashrc
    .git-prompt.sh       /home/VirtualMachines/.git-prompt.sh
    .gitconfig           /home/VirtualMachines/.gitconfig
    vm-disk1             /home/VirtualMachines/vm-disk1

2. Optional: Use the virsh vol-wipe command to wipe a storage volume. For example, to wipe a storage volume named vm-disk1 associated with the storage pool RHEL-SP:

   # virsh vol-wipe --pool RHEL-SP vm-disk1
   Vol vm-disk1 wiped

3. Use the virsh vol-delete command to delete a storage volume. For example, to delete a storage volume named vm-disk1 associated with the storage pool RHEL-SP:

   # virsh vol-delete --pool RHEL-SP vm-disk1
   Vol vm-disk1 deleted