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Sysadmin/Add resources to a VM (view source)
Revision as of 17:04, 27 February 2022
, 17:04, 27 February 2022document some disk file wizardry
sudo virsh start "name_of_vm"
sudo virsh start "name_of_vm"
=== Extending the disk file of a VM ===
=== Extending a raw disk image ===
This procedure applies to full-disk images containing an MBR partition table.
**NOTE: Any VM using this disk must be shut down beforehand, or you'll corrupt the filesystem!**
First, append some space at the end of the disk:
dd if=/dev/zero bs=1M count=$((1024-256)) >>example-boot.img
Then extend the partition to fill the entire disk:
parted example-boot.img
(parted) resizepart 1
End? [267MB]? -1
(parted) p
Model: (file)
Disk /var/lib/libvirt/images/boot/example-boot.img: 1074MB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags:
Number Start End Size Type File system Flags
1 1049kB 1073MB 1072MB primary ext4 boot
(parted) quit
Now create device nodes for the new partition table:
# kpartx -av lightwave-boot-new.img
add map loop7p1 (253:4): 0 2093152 linear 7:7 2048
Grow the filesystem inside the partition (resize2fs requires an fsck beforehand):
# e2fsck -f /dev/mapper/loop7p1
# resize2fs /dev/mapper/loop7p1
Now loopback-mount your grown up filesystem to check if it's healthy:
# mount /dev/mapper/loop7p1 /mnt
# df -h /mnt
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/loop7p1 986M 112M 820M 12% /mnt
Don't forget to unmount the filesystem and undefine the loopback devices!
umount /mnt
kpartx -d lightwave-boot-new.img
Et voilà!
=== Extending a QCOW disk file ===
Create a file containing the amount of space you want to add to the VM
Create a file containing the amount of space you want to add to the VM