This is an old revision of the document!
- virtmanagerhell
- Jonathan Haack
- Haack's Networking
- netcmnd@jonathanhaack.com
This is all very old fyi and not current or helpful; might delete it soon. Resize an .img with virt-manager, for example, expanding a 64GB disk to a 124GB disk. Start by installing the optional tools for this:
sudo apt install libguestfs-tools
After that, confirm the location of your virtual machine. You need to know the actual name of the .img file for this to work. Usually (unless it was changed by someone), this is the name that appears in the virt-manager window.
virsh dumpxml putnameofimagehere | xpath -e /domain/devices/disk/source
Navigate to the directory it spit out, and back up the image and rename it before you proceed:
cd /var/lib/libvirt/images/ sudo cp /var/lib/libvirt/images/putnameofimagehere.img /var/lib/libvirt/images/putnameofimagehere.img.bak
Once you know the name of the .img file and the location of it, prepare the virtual file systems for expansion:
virt-filesystems --long --parts --blkdevs -h -a /var/lib/libvirt/images/putnameofimagehere.img
Build a new, larger, container for the final disk, and set it aside for the merge/expansion that the tools are going to provide:
truncate -s 128G /var/lib/libvirt/images/outdisk
Now it is time to resize the existing image, using the container you just created:
virt-resize --expand /dev/sda2 /var/lib/libvirt/images/putnameofimagehere.img /var/lib/libvirt/images/outdisk
Okay, now we need to rename the new image we created to the name that virt-manager is looking for, i.e., the name of the original image. Remember, you should have the .bak file you made earlier in case this does not work. This is done as follows:
cp /var/lib/libvirt/images/putnameofimagerhere.img /var/lib/libvirt/images/putnameofimagerhere.img.old mv /var/lib/libvirt/images/outdisk /var/lib/libvirt/images/putnameofimagehere.img
Made yet another attempt to do by command line in 2022. Install packages required for resizing virtual hard disks and for listing partitions inside virtual hard disks.
apt install qemu-img kpartx
Add 50G of size to the emulated physical hard disk. This is not to be confused with adding space to, or extending, the partition inside it.
qemu-img resize debian10.img +50G
Mount the image file in the present directory, and show all of its mappings.
kpartx -v -a debian10.img
Now, it is time to extend the partition. Your loops might have different #s after, use tab to find the right one (prolly largest #).
parted /dev/loopXX print
You will get output like this:
Model: Unknown (unknown) Disk /dev/loopXX: 142GB Sector size (logical/physical): 512B/512B Partition Table: loop Disk Flags: Number Start End Size File system Flags 1 0.00B 142GB 142GB ext4
Remove the appropriate mapping. In my case, I am extending the boot volume of a virtual machine, so it was entry 1.
parted /dev/loopXX rm 1
Extend the partition from the start of the mapping you removed to the upper size limit listed in Disk.
parted /dev/loopXX mkpart primary ext4 0.00B 142GB
Verify the new mapping.
parted /dev/loopXX print
Run fsck before resizing the file system. You here appending “p1” to the name in order to make a new partition or mapping.
e2fsck -f /dev/mapper/loopXXp1
Extend the file system inside the partition to the entirety of the partition table.
resize2fs /dev/mapper/loopXXp1
Unmount the image
kpartx -d debian10.img
After messing around with this, and succeeding 1 time in resizing the drive this way, I decided that just issuing apt install qemu-img kpartx and then expanding within the VM's gparted GUI was far easier. It does require moving and/or deprecating swap (or other earlier partitions) or you cannot merge the file system.
— oemb1905 2022/08/08 00:37
